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We are surrounded
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by extraordinary feats of engineering,
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constantly pushing the boundaries of what's possible.
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Without engineering, there'd be no modern world.
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Gigantic cities, amazing infrastructure,
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and ingenious inventions.
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Engineering is the key to turn dreams into reality.
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To reach these dizzying heights,
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today's technology
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relies on breakthroughs made by ancient engineers.
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It's mind boggling how they did this.
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How did early civilizations
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build on such a scale?
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They raised the bar for construction
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in a way that no one thought possible.
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The sheer engineering ability
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that is, in itself, impressive.
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By defying the known laws of physics
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and daring to dream big,
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they constructed wonders of the world,
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from gigantic pyramids to awe inspiring temples
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and mighty fortresses,
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all with the simplest of tools.
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Cannot imagine the skills people would have needed
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to build like this.
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Now it's possible to unearth the secrets
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of the first engineers.
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They managed to construct edifices
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that have survived the ravages of time.
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And reveal how their genius
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laid the foundations for everything we build today.
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(dramatic music)
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In the modern world, military power is vital.
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You're thinking about how you want to attack your enemy
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or how people will be attacking you.
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Nations arm themselves to the teeth
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with guns, rockets, aircraft, the list is endless.
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Groundbreaking new technology
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that gives one side or other, the advantage.
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Globally,
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defense costs around $2,000,000,000,000 a year.
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We want to be secure.
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And key to all military strategy,
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impregnable defensive structures
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to protect systems and personnel from attack.
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Troops need somewhere to rest, to recuperate, to train.
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Bases built with solid walls,
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carved into mountains, bunkered deep underground,
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or constructed beneath the ice.
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But these modern defenses wouldn't have been possible
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without ancient engineering breakthroughs,
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leading to the most iconic defensive structure of all time,
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this is the history of the castle.
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(atmospheric music)
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(whooshing sounds)
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(atmospheric music)
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During the Middle Ages,
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Europe witnessed the astonishing evolution of the castle
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and two countries
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would see the greatest concentration of these structures
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anywhere in the world.
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There were castles built all across Europe in this period,
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but what's happening in England
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and what's happening in Wales
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provides us with a wonderful set of insights
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into the way in which the castle evolves.
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The conquest of wild and inaccessible Wales
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came at a time
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when castles were an essential feature of warfare.
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The Normans, invading from France, had overwhelmed England
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with the help of a network of castles across the country.
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The castle was a pivotal weapon
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{\an8}in the Norman occupation of the 11th century.
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But to take control of this hostile territory,
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totally new castle technology was required.
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And their efforts would climax spectacularly here,
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at Caerphilly Castle, South Wales.
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Caerphilly is an absolute masterpiece of castle design.
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This vast and impregnable military bastion
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was the last word in medieval engineering,
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a daunting prospect for any would-be attacker.
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Caerphilly stands out as a castle design
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{\an8}because centuries of improvement,
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{\an8}centuries of innovation are all brought together
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{\an8}in one coherent whole.
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What's particularly noticeable
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is the use of water to defend the walls,
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but it's also a concentric castle design,
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it really is a magnificent engineering achievement.
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Here we're talking about 30 acres of castle,
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multiple walls, multiple moats, lakes,
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this is castle building on a grand scale.
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Perhaps the greatest castle on earth,
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Caerphilly was the first super castle.
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Caerphilly lies at the edge of the Rhymney Valley
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in South Wales,
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and is the largest castle in the country.
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It's built at lightning speed,
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a workforce of hundreds running into thousands
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and it's not just stonework at Caerphilly,
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{\an8}there's real civil engineering going on.
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Vast and sophisticated water defenses,
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an ingenious and impregnable system of concentric walls,
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creating impassable killing zones.
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It's an example
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{\an8}of the way in which the castle design evolves
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{\an8}to take account of particular weaknesses
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that had been identified in castles before.
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Grand circular turrets,
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watchtowers that proved impossible to undermine,
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and enough space and water supplies
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to withstand the longest siege.
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Caerphilly and other 13th century super castles
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were so brilliantly engineered
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that any attack would likely prove futile.
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But how did medieval builders and architects
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manage to create such extraordinary structures?
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The last of the great super castles
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were built more than 500 years ago,
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but these mighty medieval fortresses
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and the construction techniques they pioneered
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have influenced defensive engineering
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up to the present day.
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(atmospheric music)
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Although modern armies no longer build castles,
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they still need strong, secure buildings
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to protect people, valuable objects, and political systems,
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nowhere more so than in the high tech world
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of national security.
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We still want to be secure in our buildings
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and make sure that we protect what's inside the building,
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so, in a way, we're using similar security principles
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from medieval castles.
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Today,
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one of the most secure military bases in the world
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is the Cheyenne Mountain Complex in Colorado Springs.
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Indebted to the ideas and engineering
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of the great castle builders of the Middle Ages
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and just like Caerphilly, it's famed for being impregnable.
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It's been designed to withstand any type of threat,
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{\an8}even electromagnetic pulse or nuclear attack.
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This giant bunker
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was built under 2000 feet of solid granite,
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tough enough to withstand a nuclear, biological,
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or electromagnetic attack.
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The influence of medieval castle builders is everywhere
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in Cheyenne,
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beginning at the front door.
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Medieval engineers understood that the gate house
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was the crucial point for security
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and we see this reflected in the design of Cheyenne,
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with its two giant blast doors.
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Each is made of concrete and steel
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three and a half feet thick, weighing over 20 tons.
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Cheyenne's effectiveness
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rests on being engineered for maximum strength
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and the story of the medieval castle
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was driven by the same impetus.
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But where did the ideas
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behind these ultimate fortresses originate?
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(whooshing sounds)
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Throughout the ancient world,
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early civilizations built defenses
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to protect towns, cities, and territory.
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Ancient literature, from the Bible to the Trojan War,
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gives vivid accounts of cities under siege.
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And, in the Classical Era,
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the Romans became masters of the construction
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of fortified settlements,
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as their empire spread across Europe, Africa, and Asia.
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Rome built a network of forts and walls
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to separate the empire from its enemies.
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One of the best known is Hadrian's Wall
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in northern Britain, stretching over 70 miles.
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When the Romans invaded in 43AD,
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they moved steadily across Britain,
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gathering territory, building roads, building fortresses.
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Behind Hadrian's Wall were forts,
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evenly spaced a half day's march apart,
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so each could respond quickly if another was attacked.
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Early forts were built from timber,
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replaced by stone as they became more established.
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But midway through the first century, Rome was under attack,
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so the Romans abandoned Britain
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to take care of matters back home.
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Britain wouldn't see defenses built on this scale again
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for centuries to come,
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when a new invading force
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put up its own defensive structures.
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Clues to their nature can be found on an artwork
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depicting one of the most famous battles in history.
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(men shouting)
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William the Conqueror's invasion of England in 1066
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would forever change the country's landscape and destiny.
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To establish regional power bases throughout the land,
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the Normans built something
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never seen before on these shores, castles.
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The castle was, arguably,
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the key innovation that the Normans bring to England,
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castles were scarcely known in England
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and, for this reason, the English,
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in spite of their love of fighting,
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could only put up a weak show of resistance
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to their enemies.
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Wherever William marched his army,
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he built a new castle,
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in a style known as motte-and-bailey.
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It's a move from what would be seen as kind of a fort,
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to what we would understand
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as something very obviously a castle.
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They were built in places
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that were strategically important or visually important
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so that these new castles,
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these new symbols of dominion and subjugation,
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could be seen for miles around,
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so that it was very clear that there was a new lord in town.
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It is believed
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that as many as 1000 motte-and-bailey castles
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were built throughout Britain by the Normans,
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but none have survived intact.
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So how can their construction secrets be understood?
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Luckily, the Normans left behind a blueprint
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showing how it was done.
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The evidence is woven into a unique historical document.
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In a museum in the French city of Bayeux, in Normandy,
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hangs the world famous Bayeux Tapestry.
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It depicts
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events leading up to the conquest of England in 1066.
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The Bayeux Tapestry, it's absolute gold dust
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because it gives you an artist's impression
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of what these early castles look like.
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The tapestry reveals that early castles
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were nothing like the mighty edifices of later years.
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It's clear from the Bayeux Tapestry
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that they're being, first and foremost,
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fashioned in wood and constructed out of wood.
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The motte element
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was a large mound of piled up earth,
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at the top, a wooden tower was constructed.
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To build a motte you are shifting a lot of earth,
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perhaps 20 or 30,000 tons of earth,
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so it's backbreaking work for hundreds of people.
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One of the key advantages of having the motte, of course,
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was it gave you height,
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it also made it very, very difficult to attack on horseback
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or even on foot because you'd have to clamber up that slope.
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Below the motte, the bailey was built.
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The bailey was the economic heart of the castle,
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this is where the forges were,
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the merchants traded, the houses,
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but the lord lived in his defensive castle
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up at the top of the motte.
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There are several reasons
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why none of these early castles
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survive in their original form.
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One is a fatal flaw in their design
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that attackers could all too easily exploit.
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Throughout the world,
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there is one destructive element
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that when it takes hold, leaves a trail of devastation.
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From wildfires in California and Australia,
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to skyscrapers collapsing
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as they're turned into burnt out shells,
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fire can quickly become humanity's worst enemy.
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Fire is always a risk,
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whether accidentally started from within
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or whether you have fire brandishing attackers without.
268
00:14:09,149 --> 00:14:11,174
The original motte-and-bailey castles
269
00:14:11,174 --> 00:14:15,170
were constructed with wooden palisades,
270
00:14:15,170 --> 00:14:18,508
wooden houses, wooden keeps,
271
00:14:18,508 --> 00:14:20,856
so they could easily be ignited by bonfires
272
00:14:20,856 --> 00:14:25,423
lit against their outer wooden fences, hurling torches,
273
00:14:26,621 --> 00:14:29,473
or by archers shooting fire arrows.
274
00:14:32,076 --> 00:14:35,568
When fire took hold, those inside were forced to flee,
275
00:14:35,568 --> 00:14:38,000
allowing the attackers to take them prisoner
276
00:14:38,000 --> 00:14:39,813
or to slaughter them.
277
00:14:40,782 --> 00:14:42,482
The use of fire as a weapon
278
00:14:42,482 --> 00:14:45,593
has continued right up to modern times.
279
00:14:51,490 --> 00:14:53,318
During the Second World War,
280
00:14:53,318 --> 00:14:57,238
incendiary bombs were dropped on enemy targets,
281
00:14:57,238 --> 00:15:01,093
designed to start large scale firestorms on the ground.
282
00:15:02,028 --> 00:15:04,571
Incendiary bombs contained thermite,
283
00:15:04,571 --> 00:15:08,235
a mixture of aluminum powder and iron oxide
284
00:15:08,235 --> 00:15:10,863
that burns at a very high temperature.
285
00:15:10,863 --> 00:15:14,228
They were encased in an element like magnesium
286
00:15:14,228 --> 00:15:16,520
which, itself, is highly flammable
287
00:15:16,520 --> 00:15:18,920
and they might have also contained materials
288
00:15:18,920 --> 00:15:20,507
like oil or pitch,
289
00:15:20,507 --> 00:15:24,010
which would quickly set fire and spread the fire.
290
00:15:24,010 --> 00:15:24,851
The German Luftwaffe
291
00:15:24,851 --> 00:15:28,014
dropped these weapons on London during the Blitz
292
00:15:28,014 --> 00:15:31,404
and allied air forces used them to create firestorms
293
00:15:31,404 --> 00:15:34,121
in Dresden and Tokyo.
294
00:15:34,121 --> 00:15:38,231
Incendiary bombs can destroy vast areas of territory,
295
00:15:38,231 --> 00:15:41,700
they can change the face of cities in seconds
296
00:15:41,700 --> 00:15:43,849
with really sudden dramatic impact,
297
00:15:43,849 --> 00:15:47,090
if thousands of them are dropped, there's nowhere to run,
298
00:15:47,090 --> 00:15:48,503
there's nowhere to hide.
299
00:15:50,200 --> 00:15:52,207
Fire could have the same devastating impact
300
00:15:52,207 --> 00:15:54,483
on a medieval wooden castle.
301
00:15:56,792 --> 00:15:59,448
So engineers needed to develop structures
302
00:15:59,448 --> 00:16:02,154
that would be stronger, longer lasting,
303
00:16:02,154 --> 00:16:06,010
and, most importantly, fireproof.
304
00:16:06,010 --> 00:16:10,853
The answer, improved technology and a new building material,
305
00:16:11,840 --> 00:16:13,000
stone.
306
00:16:13,000 --> 00:16:16,381
The first examples were built as much as a display of power
307
00:16:16,381 --> 00:16:19,150
as for military purposes.
308
00:16:19,150 --> 00:16:21,006
The Normans began to build castles in stone
309
00:16:21,006 --> 00:16:24,265
as a powerful symbol that they were here to stay,
310
00:16:24,265 --> 00:16:26,978
that their invasion was permanent.
311
00:16:26,978 --> 00:16:27,811
They would have to
312
00:16:27,811 --> 00:16:29,941
be jaw-droppingly impressive,
313
00:16:29,941 --> 00:16:33,913
seemingly invincible, and built to last.
314
00:16:34,778 --> 00:16:37,146
William the Conqueror laid down the template
315
00:16:37,146 --> 00:16:40,323
with one of the mightiest castles ever built.
316
00:16:47,318 --> 00:16:50,379
Infamous as a terrifying Tudor prison
317
00:16:50,379 --> 00:16:54,083
and renowned as the home of the crown jewels,
318
00:16:54,083 --> 00:16:56,113
the Tower of London.
319
00:16:57,322 --> 00:16:58,202
The White Tower
320
00:16:58,202 --> 00:17:01,823
is the most recognizable castle keep in the world.
321
00:17:03,215 --> 00:17:04,530
At the time,
322
00:17:04,530 --> 00:17:06,900
nothing of this scale had been built in Britain
323
00:17:06,900 --> 00:17:08,191
since the Romans.
324
00:17:08,191 --> 00:17:11,674
William's white tower in London was completely different
325
00:17:11,674 --> 00:17:13,009
because it was made of stone
326
00:17:13,009 --> 00:17:15,092
that was imported from Normandy
327
00:17:15,092 --> 00:17:17,340
and he built it in that part of the River Thames
328
00:17:17,340 --> 00:17:20,181
to dominate the people of London,
329
00:17:20,181 --> 00:17:22,958
to say, I am your new king.
330
00:17:22,958 --> 00:17:24,630
{\an8}If you're sailing up the Thames,
331
00:17:24,630 --> 00:17:28,732
{\an8}coming to London for the first time, bang, there it is,
332
00:17:28,732 --> 00:17:32,763
just to say, I'm in charge, I am all powerful.
333
00:17:36,862 --> 00:17:39,457
The tower was a high security base
334
00:17:39,457 --> 00:17:43,241
for the royal family and their military entourage.
335
00:17:43,241 --> 00:17:45,530
The White Tower had a very key feature
336
00:17:45,530 --> 00:17:49,061
and that is that the entrance was on the first story,
337
00:17:49,061 --> 00:17:51,503
so you couldn't get in at ground level,
338
00:17:51,503 --> 00:17:53,640
it was built with immense walls,
339
00:17:53,640 --> 00:17:55,743
it was completely impregnable.
340
00:17:56,593 --> 00:17:58,855
Unlike a typical royal palace complex
341
00:17:58,855 --> 00:18:01,112
spread across a number of buildings,
342
00:18:01,112 --> 00:18:02,610
here, for security reasons,
343
00:18:02,610 --> 00:18:05,007
the meeting hall, chapel, and bedrooms
344
00:18:05,007 --> 00:18:09,633
are all stacked on top of one another in a high rise design.
345
00:18:09,633 --> 00:18:13,864
William was never to see the tower in its full glory,
346
00:18:13,864 --> 00:18:18,864
it wasn't completed until 1100, 13 years after his death.
347
00:18:18,892 --> 00:18:21,509
But his fortress would play a central role
348
00:18:21,509 --> 00:18:23,026
in British history,
349
00:18:23,026 --> 00:18:27,183
a place notorious for murder and mystery.
350
00:18:30,893 --> 00:18:35,323
Two of Henry VIII's wives were executed at the tower
351
00:18:35,323 --> 00:18:38,021
and Guy Fawkes was imprisoned here
352
00:18:38,021 --> 00:18:40,825
following his attempt to blow up parliament.
353
00:18:40,825 --> 00:18:44,925
Richard III reputedly had his two young nephews murdered
354
00:18:44,925 --> 00:18:48,613
and their bodies hidden behind a wall.
355
00:18:48,613 --> 00:18:53,443
And in 1861, a thief tried to steal the crown jewels.
356
00:18:57,008 --> 00:18:58,209
For centuries,
357
00:18:58,209 --> 00:19:00,254
the tower has stood on the banks of the Thames
358
00:19:00,254 --> 00:19:02,263
as a potent symbol.
359
00:19:03,130 --> 00:19:04,555
Today, the super rich and the powerful
360
00:19:04,555 --> 00:19:09,555
continue to use tall or grand buildings to impress.
361
00:19:09,590 --> 00:19:11,682
Built to honor the Kim dynasty,
362
00:19:11,682 --> 00:19:16,682
North Korea's Rungrado Stadium is the largest on earth.
363
00:19:16,760 --> 00:19:19,540
For centuries, countries have competed for the prestige
364
00:19:19,540 --> 00:19:23,260
of having the tallest building in the world.
365
00:19:23,260 --> 00:19:24,667
Upon completion in 2010,
366
00:19:24,667 --> 00:19:27,480
the Burj Khalifa seized the crown
367
00:19:27,480 --> 00:19:29,055
for the United Arab Emirates,
368
00:19:29,055 --> 00:19:33,933
standing a whopping 2,716.5 feet high.
369
00:19:35,829 --> 00:19:38,914
And there are those with a few billion dollars to spare
370
00:19:38,914 --> 00:19:41,723
who choose to build their own towers.
371
00:19:43,012 --> 00:19:45,929
(whooshing sounds)
372
00:19:49,462 --> 00:19:52,593
(soft music)
373
00:19:52,593 --> 00:19:53,924
Back in medieval England,
374
00:19:53,924 --> 00:19:56,032
William the Conqueror's stone tower
375
00:19:56,032 --> 00:19:58,674
was the first of its kind.
376
00:19:58,674 --> 00:20:01,571
But, subsequently, a vast building project
377
00:20:01,571 --> 00:20:03,901
would take the concept of the castle
378
00:20:03,901 --> 00:20:07,453
and castle engineering to a whole new level.
379
00:20:08,997 --> 00:20:12,045
Rochester Castle stands on the banks of the River Medway
380
00:20:12,045 --> 00:20:14,643
in the English county of Kent.
381
00:20:15,636 --> 00:20:19,251
It was designed with some radical engineering innovations
382
00:20:19,251 --> 00:20:24,163
to be ready for any attack, foreign or domestic.
383
00:20:25,190 --> 00:20:26,861
Traces of damage inflicted by enemies
384
00:20:26,861 --> 00:20:30,712
are still visible on the fabric of the castle today
385
00:20:30,712 --> 00:20:33,617
but they weren't left by invading forces,
386
00:20:33,617 --> 00:20:35,878
rather, a homegrown assault.
387
00:20:35,878 --> 00:20:37,814
The design of Rochester is unique
388
00:20:37,814 --> 00:20:39,491
for two very important reasons.
389
00:20:39,491 --> 00:20:42,413
The first is that it's the first tower in the country
390
00:20:42,413 --> 00:20:44,215
to be built on four stories,
391
00:20:44,215 --> 00:20:45,048
so it's much taller
392
00:20:45,048 --> 00:20:47,341
than any other tower that's been built
393
00:20:47,341 --> 00:20:50,971
and secondly, is the construction of a forecastle.
394
00:20:50,971 --> 00:20:52,308
The forecastle
395
00:20:52,308 --> 00:20:55,806
is designed to protect a castle's entranceway.
396
00:20:55,806 --> 00:20:57,384
In any fortification,
397
00:20:57,384 --> 00:21:00,266
the weak point is always gonna be the entrance.
398
00:21:00,266 --> 00:21:01,299
At Rochester,
399
00:21:01,299 --> 00:21:04,677
a large stone extension houses a giant waiting room
400
00:21:04,677 --> 00:21:09,480
and, crucially, conceals the main gate from attack.
401
00:21:09,480 --> 00:21:11,925
Any assault would now involve an extended approach
402
00:21:11,925 --> 00:21:14,210
that could only be made on foot,
403
00:21:14,210 --> 00:21:17,859
an attacking force would be helplessly exposed.
404
00:21:17,859 --> 00:21:18,945
The way it is engineered
405
00:21:18,945 --> 00:21:22,911
is specifically to defend with the fewest number of people
406
00:21:22,911 --> 00:21:25,503
against the maximum numbers of attackers.
407
00:21:28,827 --> 00:21:31,960
(keypad beeping)
408
00:21:31,960 --> 00:21:35,068
Entrance security is still evolving today,
409
00:21:35,068 --> 00:21:38,071
there are countless ways to keep a door shut
410
00:21:38,071 --> 00:21:43,071
and the world's most famous vault is at Fort Knox.
411
00:21:47,424 --> 00:21:48,989
Fort Knox in Kentucky
412
00:21:48,989 --> 00:21:52,263
is home to the United States Bullion Depository,
413
00:21:53,361 --> 00:21:56,780
it stores the country's precious metal reserves
414
00:21:57,658 --> 00:22:01,506
including over 4,000 tons of gold.
415
00:22:01,506 --> 00:22:04,376
The expression, it's like trying to get into Fort Knox,
416
00:22:04,376 --> 00:22:08,015
implies a really high level of security
417
00:22:08,015 --> 00:22:09,999
and certainly, in the case of Fort Knox,
418
00:22:09,999 --> 00:22:11,110
what we're talking about
419
00:22:11,110 --> 00:22:14,574
is somewhere that's nearly impossible to access.
420
00:22:14,574 --> 00:22:16,674
Fort Knox can only be entered
421
00:22:16,674 --> 00:22:20,837
after negotiating four perimeter fences, armed guards,
422
00:22:20,837 --> 00:22:24,661
and a state-of-the-art electronic security system.
423
00:22:24,661 --> 00:22:28,580
The building itself is seemingly impregnable,
424
00:22:28,580 --> 00:22:31,846
it's made of concrete lined granite and reinforced steel,
425
00:22:31,846 --> 00:22:33,918
enabling it to withstand attack.
426
00:22:33,918 --> 00:22:35,142
And, just in case,
427
00:22:35,142 --> 00:22:39,014
digital technology presents a final barrier.
428
00:22:39,014 --> 00:22:40,436
The security codes are shared
429
00:22:40,436 --> 00:22:42,343
amongst a number of people
430
00:22:42,343 --> 00:22:45,880
to make it really difficult to access this building.
431
00:22:45,880 --> 00:22:47,491
So far, at least,
432
00:22:47,491 --> 00:22:50,653
no one has ever come close to breaking in.
433
00:22:51,585 --> 00:22:54,502
(whooshing sounds)
434
00:22:59,969 --> 00:23:01,879
For over 100 years,
435
00:23:01,879 --> 00:23:05,363
Rochester Castle was considered equally impregnable,
436
00:23:07,084 --> 00:23:10,586
but in 1215, a group of rebels attempted to seize control
437
00:23:10,586 --> 00:23:14,000
of this key military stronghold.
438
00:23:14,000 --> 00:23:16,102
At that time, it presented a major threat
439
00:23:16,102 --> 00:23:21,102
to the ruler of England, King John, he ordered a siege.
440
00:23:22,159 --> 00:23:25,693
John is determined to break into this gargantuan castle,
441
00:23:25,693 --> 00:23:30,095
so he throws everything he can at it for seven weeks.
442
00:23:30,095 --> 00:23:31,506
So what kind of weapons
443
00:23:31,506 --> 00:23:33,821
were at King John's disposal?
444
00:23:33,821 --> 00:23:36,061
If you want to smash your way into a building,
445
00:23:36,061 --> 00:23:39,582
you might think the easiest way is through the front door.
446
00:23:39,582 --> 00:23:43,720
Giant battering rams had been developed in ancient times,
447
00:23:43,720 --> 00:23:46,016
the Assyrians had sophisticated rams
448
00:23:46,016 --> 00:23:48,904
as early as the ninth century BC.
449
00:23:48,904 --> 00:23:51,941
Battering ram is quite an interesting piece of technology,
450
00:23:51,941 --> 00:23:52,930
the idea
451
00:23:52,930 --> 00:23:56,584
{\an8}is that when you put a large force into a small area,
452
00:23:56,584 --> 00:23:59,330
{\an8}you get a very high pressure out of it.
453
00:23:59,330 --> 00:24:01,437
In theory, such intense pressure
454
00:24:01,437 --> 00:24:04,423
would puncture the toughest of barriers,
455
00:24:05,771 --> 00:24:07,702
but the entrance to Rochester Castle
456
00:24:07,702 --> 00:24:09,347
was up on the first floor,
457
00:24:09,347 --> 00:24:12,596
protected by the forecastle, heavy doors,
458
00:24:12,596 --> 00:24:14,921
and a portcullis,
459
00:24:14,921 --> 00:24:18,275
making it impossible to maneuver a large battering ram
460
00:24:18,275 --> 00:24:20,253
anywhere near the gate.
461
00:24:21,713 --> 00:24:25,017
So King John ordered the deployment of a new weapon
462
00:24:25,017 --> 00:24:26,673
to break the siege,
463
00:24:29,927 --> 00:24:31,803
the trebuchet.
464
00:24:33,776 --> 00:24:36,931
The engineering principles behind the trebuchet
465
00:24:36,931 --> 00:24:41,213
are exactly the same as you would imagine a catapult.
466
00:24:42,700 --> 00:24:43,880
A trebuchet
467
00:24:43,880 --> 00:24:45,779
uses the energy of a falling counterweight
468
00:24:45,779 --> 00:24:47,615
to launch a projectile,
469
00:24:47,615 --> 00:24:51,196
such as a large rock contained in a sling
470
00:24:51,196 --> 00:24:53,586
attached to a lever arm.
471
00:24:53,586 --> 00:24:56,090
The counterweight is hoisted into the air
472
00:24:56,090 --> 00:24:57,967
and cocked with a pin,
473
00:24:57,967 --> 00:24:59,253
once the pin is removed,
474
00:24:59,253 --> 00:25:01,206
the counterweight immediately drops
475
00:25:01,206 --> 00:25:03,670
and the lever arm sharply rotates,
476
00:25:03,670 --> 00:25:05,941
throwing the rock hundreds of feet through the air
477
00:25:05,941 --> 00:25:08,241
towards its target.
478
00:25:08,241 --> 00:25:11,074
(whooshing sound)
479
00:25:12,471 --> 00:25:14,260
This high-tech medieval weapon
480
00:25:14,260 --> 00:25:17,540
was engineered to inflict maximum damage
481
00:25:17,540 --> 00:25:19,708
and King John had sent five of them
482
00:25:19,708 --> 00:25:22,925
to the siege of Rochester Castle.
483
00:25:22,925 --> 00:25:27,727
Those hiding inside castle walls might've felt pretty safe
484
00:25:27,727 --> 00:25:30,685
until their combatants on the opposite side,
485
00:25:30,685 --> 00:25:33,510
brought up their heavy artillery.
486
00:25:33,510 --> 00:25:37,449
So he's hurling great rocks, carved balls of stone
487
00:25:37,449 --> 00:25:41,065
at the castle, trying to smash his way in.
488
00:25:41,065 --> 00:25:43,705
These five machines didn't cease in their barrage,
489
00:25:43,705 --> 00:25:44,833
day and night.
490
00:25:45,690 --> 00:25:47,237
Despite being the most advanced weapons
491
00:25:47,237 --> 00:25:49,379
of their day, the king's trebuchets
492
00:25:49,379 --> 00:25:52,902
failed to dent Rochester's mighty stone walls
493
00:25:52,902 --> 00:25:57,683
or the rebel's resolve, the siege continued.
494
00:26:00,952 --> 00:26:02,275
In the modern world,
495
00:26:02,275 --> 00:26:03,667
the search for new weapons
496
00:26:03,667 --> 00:26:07,877
is still a never ending technological arms race.
497
00:26:07,877 --> 00:26:11,744
Each new weapon is counteracted by a new form of defense,
498
00:26:11,744 --> 00:26:13,889
which, in turn, creates a demand
499
00:26:13,889 --> 00:26:16,803
for more powerful attacking technology.
500
00:26:18,059 --> 00:26:20,756
Today, as ever deeper and more ambitious
501
00:26:20,756 --> 00:26:24,564
subterranean command centers are constructed,
502
00:26:24,564 --> 00:26:26,467
a new generation of weaponry
503
00:26:26,467 --> 00:26:28,905
has been developed to reach them.
504
00:26:28,905 --> 00:26:30,457
Known as bunker busters,
505
00:26:30,457 --> 00:26:33,707
these are bombs which can penetrate deep into the earth
506
00:26:33,707 --> 00:26:37,735
or right through dozens of feet of reinforced concrete
507
00:26:37,735 --> 00:26:41,812
before exploding and causing absolute devastation.
508
00:26:41,812 --> 00:26:44,562
(dramatic music)
509
00:26:46,438 --> 00:26:49,355
(whooshing sounds)
510
00:26:55,361 --> 00:26:58,854
At the 13th century siege of Rochester Castle,
511
00:26:58,854 --> 00:27:03,255
going underground was now King John's only option.
512
00:27:03,255 --> 00:27:06,165
His tactics would expose a weakness in castle design
513
00:27:06,165 --> 00:27:09,304
that even stone construction couldn't address.
514
00:27:09,304 --> 00:27:11,035
The only way John is, in the end,
515
00:27:11,035 --> 00:27:13,059
able to get into that building
516
00:27:13,059 --> 00:27:14,920
is to undermine it,
517
00:27:14,920 --> 00:27:18,493
which is to say to dig a tunnel under one corner.
518
00:27:20,967 --> 00:27:24,436
Then when the tunnel had been dug right under the wall,
519
00:27:24,436 --> 00:27:26,493
they would set fire to that timber
520
00:27:26,493 --> 00:27:28,950
and the wall would collapse.
521
00:27:28,950 --> 00:27:31,546
It caused a good proportion of the keep
522
00:27:31,546 --> 00:27:34,101
to come crashing to the ground.
523
00:27:34,101 --> 00:27:37,040
The way they use fire to undermine structures
524
00:27:37,040 --> 00:27:40,555
is by basically destroying the foundation
525
00:27:40,555 --> 00:27:42,229
that the structure is built upon
526
00:27:42,229 --> 00:27:43,891
and once the foundation has gone
527
00:27:43,891 --> 00:27:46,089
and you get a weak point in the structure,
528
00:27:46,089 --> 00:27:49,673
then the structure has no substance to stand on.
529
00:27:49,673 --> 00:27:51,584
Amazingly, even after the collapse
530
00:27:51,584 --> 00:27:53,665
of the southeast corner of the keep,
531
00:27:53,665 --> 00:27:55,973
the rebels fought on.
532
00:27:55,973 --> 00:27:58,210
In the end, it's hunger that does for them,
533
00:27:58,210 --> 00:27:59,481
it's hunger that induces them
534
00:27:59,481 --> 00:28:02,511
to eventually surrender to King John.
535
00:28:02,511 --> 00:28:03,628
The fall of Rochester
536
00:28:03,628 --> 00:28:06,155
proved that the new generation of stone castles
537
00:28:06,155 --> 00:28:08,858
were not yet invulnerable,
538
00:28:08,858 --> 00:28:11,425
medieval engineers had their work cut out
539
00:28:11,425 --> 00:28:14,557
if they were to defend against tunnelers.
540
00:28:16,141 --> 00:28:19,188
And tunneling has remained a military tactic
541
00:28:19,188 --> 00:28:21,543
right up to the 20th century.
542
00:28:25,982 --> 00:28:29,010
Playing a role in some of the bloodiest military campaigns
543
00:28:29,010 --> 00:28:30,803
of the modern era,
544
00:28:32,342 --> 00:28:35,739
during the Second World War, Japanese soldiers used tunnels
545
00:28:35,739 --> 00:28:39,167
on the Pacific Island of Iwo Jima,
546
00:28:39,167 --> 00:28:41,238
constructing miles of hidden passageways
547
00:28:41,238 --> 00:28:44,853
to defend against or attack American forces.
548
00:28:46,338 --> 00:28:48,451
Tunnels were also used to great effect
549
00:28:48,451 --> 00:28:52,543
during the Vietnam War of the 1960s and '70s.
550
00:28:53,701 --> 00:28:57,245
Viet Cong built a huge network of tunnels
551
00:28:57,245 --> 00:28:59,423
about 20 feet below ground,
552
00:28:59,423 --> 00:29:02,875
these tunnels would allow soldiers to travel for miles
553
00:29:02,875 --> 00:29:06,133
to conduct surveillance, to set traps,
554
00:29:06,133 --> 00:29:08,674
or to launch surprise attacks.
555
00:29:08,674 --> 00:29:09,890
After which,
556
00:29:09,890 --> 00:29:12,333
they could disappear underground to safety.
557
00:29:13,250 --> 00:29:17,179
Tunneling is a tried and tested dirty trick of war.
558
00:29:17,179 --> 00:29:20,096
(whooshing sounds)
559
00:29:25,804 --> 00:29:28,229
And the undermining of Rochester Castle
560
00:29:28,229 --> 00:29:31,516
proved a valuable lesson to medieval engineers.
561
00:29:31,516 --> 00:29:33,453
When they came to rebuild the fortress,
562
00:29:33,453 --> 00:29:36,916
they introduced a radical new feature.
563
00:29:36,916 --> 00:29:38,530
The square tower at Rochester
564
00:29:38,530 --> 00:29:40,742
was replaced by a round tower.
565
00:29:40,742 --> 00:29:44,835
Circular towers are structurally stronger
566
00:29:44,835 --> 00:29:46,573
than square towers,
567
00:29:46,573 --> 00:29:49,700
they have less points of weakness.
568
00:29:49,700 --> 00:29:50,818
When a projectile
569
00:29:50,818 --> 00:29:53,813
hits the corner or edge of a square tower,
570
00:29:54,926 --> 00:29:57,649
it can easily bring it down
571
00:29:57,649 --> 00:29:59,336
but if it hits a circular tower
572
00:29:59,336 --> 00:30:02,133
it's more likely to be harmlessly deflected.
573
00:30:03,867 --> 00:30:06,352
Circular towers of various kinds
574
00:30:06,352 --> 00:30:09,840
proved a game changing advance for castle security
575
00:30:11,463 --> 00:30:14,883
and the advantages weren't only structural.
576
00:30:17,467 --> 00:30:19,015
From a surveillance perspective,
577
00:30:19,015 --> 00:30:22,833
round towers gave bowmen a far wider field of vision,
578
00:30:25,656 --> 00:30:28,090
eradicating watchtower blind spots
579
00:30:28,090 --> 00:30:31,683
created by the 90 degree corners of square towers.
580
00:30:40,640 --> 00:30:43,307
(dynamic music)
581
00:30:45,858 --> 00:30:48,971
Today, the curved wall is used by architects
582
00:30:48,971 --> 00:30:49,973
to design and build
583
00:30:49,973 --> 00:30:53,142
some of the most elaborate and jaw-dropping buildings
584
00:30:53,142 --> 00:30:54,667
in the world,
585
00:30:54,667 --> 00:30:56,450
liberation from the rectangular forms
586
00:30:56,450 --> 00:30:59,365
that traditionally dominated city scapes.
587
00:30:59,365 --> 00:31:01,969
The Absolute World tower in Canada,
588
00:31:01,969 --> 00:31:05,330
where you've got these amazing curved towers
589
00:31:05,330 --> 00:31:07,964
and the taller one is actually nicknamed Marilyn Monroe
590
00:31:07,964 --> 00:31:12,258
for its iconic hourglass figure.
591
00:31:12,258 --> 00:31:15,624
Guggenheim Bilbao is one of the great buildings
592
00:31:15,624 --> 00:31:17,815
of the late 20th century
593
00:31:17,815 --> 00:31:22,466
and it's a building that looks utterly impossible.
594
00:31:22,466 --> 00:31:24,647
There's architects wanting to explore,
595
00:31:24,647 --> 00:31:27,959
not just the possibility of building circular buildings,
596
00:31:27,959 --> 00:31:31,534
but of completely defying this square box
597
00:31:31,534 --> 00:31:36,534
and building things that look utterly unbuildable.
598
00:31:37,924 --> 00:31:40,841
(whooshing sounds)
599
00:31:43,833 --> 00:31:46,835
By the time Rochester got its round tower,
600
00:31:46,835 --> 00:31:48,548
other elements of castle engineering
601
00:31:48,548 --> 00:31:50,264
were also improving,
602
00:31:50,264 --> 00:31:52,324
with lessons learned far from the battlefields
603
00:31:52,324 --> 00:31:54,898
of England and Wales.
604
00:31:54,898 --> 00:31:57,664
From its seventh century emergence in the Middle East,
605
00:31:57,664 --> 00:32:00,135
the Islamic faith spread far and wide,
606
00:32:00,135 --> 00:32:02,893
east towards India into Northern Africa
607
00:32:02,893 --> 00:32:05,403
and up into Southwest Europe.
608
00:32:06,713 --> 00:32:08,260
By the 11th century,
609
00:32:08,260 --> 00:32:10,533
knights from Europe were embarking on crusades
610
00:32:10,533 --> 00:32:14,544
to recover the Holy land from Islamic rule.
611
00:32:14,544 --> 00:32:18,703
Here, they'd build new fortresses on a massive scale.
612
00:32:19,909 --> 00:32:22,477
One of the most powerful of these crusader castles
613
00:32:22,477 --> 00:32:25,216
can still be found 25 miles west
614
00:32:25,216 --> 00:32:28,623
of the city of Homs in Syria near the Lebanese border,
615
00:32:32,995 --> 00:32:34,733
Crac des Chevaliers.
616
00:32:36,872 --> 00:32:38,315
Crac des Chevaliers was unique
617
00:32:38,315 --> 00:32:40,139
because it's one of the earliest examples
618
00:32:40,139 --> 00:32:42,165
of a concentric castle,
619
00:32:42,165 --> 00:32:43,308
which means that the castle
620
00:32:43,308 --> 00:32:46,072
sits within its own curtain wall.
621
00:32:46,072 --> 00:32:47,301
Concentric castles
622
00:32:47,301 --> 00:32:49,554
consisted of an outer circuit wall
623
00:32:49,554 --> 00:32:51,288
with built-in round towers
624
00:32:51,288 --> 00:32:56,288
and an inner wall built higher with additional towers.
625
00:32:56,370 --> 00:32:57,689
The idea is that that inner wall
626
00:32:57,689 --> 00:33:01,310
can protect and defend the top of the outer wall,
627
00:33:01,310 --> 00:33:05,060
and that these two walls are broadly parallel.
628
00:33:05,060 --> 00:33:06,766
With the concentric layout,
629
00:33:06,766 --> 00:33:09,458
defenders could protect the outer perimeter from attack
630
00:33:09,458 --> 00:33:11,710
and then fall back, if need be,
631
00:33:11,710 --> 00:33:14,343
into the center of the castle.
632
00:33:15,834 --> 00:33:19,691
The wall within the wall at Crac was highly influential
633
00:33:19,691 --> 00:33:22,163
and not just in the medieval world,
634
00:33:23,130 --> 00:33:25,660
the concept has been endlessly reused
635
00:33:25,660 --> 00:33:30,660
to keep people out and sometimes to keep people in,
636
00:33:30,708 --> 00:33:32,766
right up to modern times.
637
00:33:32,766 --> 00:33:35,516
(dramatic music)
638
00:33:39,332 --> 00:33:41,749
(soft music)
639
00:33:43,228 --> 00:33:44,399
During the Cold War
640
00:33:44,399 --> 00:33:46,640
in the second half of the 20th century,
641
00:33:46,640 --> 00:33:49,473
control of Europe was divided between NATO in the west
642
00:33:49,473 --> 00:33:53,040
and the Warsaw Pact in the east.
643
00:33:53,040 --> 00:33:53,929
Berlin in Germany
644
00:33:53,929 --> 00:33:56,933
was initially shared between the two blocks,
645
00:33:57,875 --> 00:34:01,314
but in August, 1961, in just two weeks,
646
00:34:01,314 --> 00:34:02,409
east German forces
647
00:34:02,409 --> 00:34:07,082
erected a makeshift barbed wire and concrete block wall,
648
00:34:07,082 --> 00:34:10,313
dividing one side of the city from the other,
649
00:34:11,299 --> 00:34:13,393
the Berlin Wall.
650
00:34:14,481 --> 00:34:16,820
Over the following months and years,
651
00:34:16,820 --> 00:34:18,993
the wall was further reinforced.
652
00:34:20,071 --> 00:34:23,075
The Berlin Wall was actually constructed of two walls
653
00:34:23,075 --> 00:34:24,567
with an area in between
654
00:34:24,567 --> 00:34:29,203
that was filled with watchtowers, anti-vehicle trenches,
655
00:34:29,203 --> 00:34:30,930
guard dog runs,
656
00:34:30,930 --> 00:34:32,710
in effect it was a killing zone,
657
00:34:32,710 --> 00:34:34,221
much like we might say
658
00:34:34,221 --> 00:34:37,753
the area between the concentric walls of a medieval castle.
659
00:34:45,184 --> 00:34:48,101
(whooshing sounds)
660
00:34:53,491 --> 00:34:56,382
The medieval castle, Crac des Chevaliers,
661
00:34:56,382 --> 00:34:59,017
also had some defensive tricks up its sleeve.
662
00:34:59,017 --> 00:35:00,729
So, half the battle's won
663
00:35:00,729 --> 00:35:02,891
when you're creating an impregnable fortress,
664
00:35:02,891 --> 00:35:05,743
if you stick it up on a nice rocky outcrop.
665
00:35:06,741 --> 00:35:08,600
Over 2,000 feet high,
666
00:35:08,600 --> 00:35:11,135
surrounded by steep inclines,
667
00:35:11,135 --> 00:35:16,007
the landscape gave this castle a defensive headstart.
668
00:35:16,007 --> 00:35:16,840
Any approach
669
00:35:16,840 --> 00:35:19,740
would leave an attacker dangerously exposed.
670
00:35:19,740 --> 00:35:21,600
Crac des Chevaliers
671
00:35:21,600 --> 00:35:24,280
also has a very distinctive entranceway,
672
00:35:24,280 --> 00:35:25,395
it's called a bent entrance
673
00:35:25,395 --> 00:35:27,492
in which anyone entering the castle
674
00:35:27,492 --> 00:35:30,129
is essentially funneled into a bottleneck,
675
00:35:30,129 --> 00:35:32,433
making them very vulnerable to attack.
676
00:35:32,433 --> 00:35:35,172
Although it survived many assaults and sieges,
677
00:35:35,172 --> 00:35:38,029
the castle eventually fell in 1271
678
00:35:38,029 --> 00:35:41,229
and the last of its crusader knights either surrendered
679
00:35:41,229 --> 00:35:43,196
or were killed.
680
00:35:43,196 --> 00:35:45,246
Despite Crac's ultimate defeat,
681
00:35:45,246 --> 00:35:49,240
advantageous geography can boost security,
682
00:35:49,240 --> 00:35:53,130
used effectively, it will deter most would-be attackers.
683
00:35:53,130 --> 00:35:55,514
There are some astonishing later examples,
684
00:35:55,514 --> 00:35:59,075
including the Predjama Castle in Slovenia
685
00:35:59,075 --> 00:36:02,171
built in the mouth of a cave,
686
00:36:02,171 --> 00:36:03,396
Mont-Saint-Michel
687
00:36:03,396 --> 00:36:07,265
built on a tidal island in Northern France,
688
00:36:07,265 --> 00:36:09,397
and Trosky Castle in Bohemia
689
00:36:09,397 --> 00:36:13,083
constructed on a hilltop surrounded by forest.
690
00:36:18,672 --> 00:36:22,407
Unsurprisingly, engineering ideas from the Crusader wars
691
00:36:22,407 --> 00:36:25,663
traveled back home with the returning soldiers.
692
00:36:26,863 --> 00:36:28,624
It's almost like the Holy Land
693
00:36:28,624 --> 00:36:32,290
becomes a laboratory for castle design.
694
00:36:32,290 --> 00:36:33,479
In the late 12th century,
695
00:36:33,479 --> 00:36:36,221
the idea of building two concentric defensive walls
696
00:36:36,221 --> 00:36:38,423
arrived in Northern Europe.
697
00:36:40,790 --> 00:36:44,423
Dover Castle is sometimes called the key to England.
698
00:36:46,740 --> 00:36:47,668
Built by Henry II,
699
00:36:47,668 --> 00:36:49,248
it was the most expensive,
700
00:36:49,248 --> 00:36:52,593
most heavily defended fortress in the kingdom.
701
00:36:54,042 --> 00:36:56,436
Dover Castle was an immense tower
702
00:36:56,436 --> 00:36:58,924
protected by a very distinctive curtain wall,
703
00:36:58,924 --> 00:37:01,615
which had towers all the way along it
704
00:37:01,615 --> 00:37:03,671
and the key thing about Dover Castle
705
00:37:03,671 --> 00:37:06,793
was the heavily defended entranceway.
706
00:37:07,734 --> 00:37:10,828
At the heart of the castle was a giant keep,
707
00:37:10,828 --> 00:37:13,501
with walls up to 20 foot thick.
708
00:37:13,501 --> 00:37:17,116
Its outer wall incorporated 14 rectangular towers
709
00:37:17,116 --> 00:37:19,724
set on projecting plinths,
710
00:37:19,724 --> 00:37:22,515
as well as a tower with firing platforms
711
00:37:22,515 --> 00:37:26,713
and multiple narrow windows for archers and crossbowmen.
712
00:37:27,926 --> 00:37:29,679
It's believed that the crossbow
713
00:37:29,679 --> 00:37:31,871
had only recently arrived in England
714
00:37:31,871 --> 00:37:33,820
with the Battle of Hastings,
715
00:37:33,820 --> 00:37:35,841
though not a great weapon on the battlefield,
716
00:37:35,841 --> 00:37:38,757
it proved a game changer for castle defense.
717
00:37:38,757 --> 00:37:42,125
Crossbows are probably the most important weapon
718
00:37:42,125 --> 00:37:44,022
in a siege situation,
719
00:37:44,022 --> 00:37:45,720
because they are so deadly,
720
00:37:45,720 --> 00:37:50,353
they are able to pick off a well armed mounted knight
721
00:37:50,353 --> 00:37:53,747
because of their range and penetrative power.
722
00:37:53,747 --> 00:37:54,772
With the bow and arrow,
723
00:37:54,772 --> 00:37:57,799
you are basically having to use your strength
724
00:37:57,799 --> 00:38:00,402
to pull the bow back,
725
00:38:00,402 --> 00:38:02,450
but the crossbow had this added feature
726
00:38:02,450 --> 00:38:04,534
where you could stand there waiting
727
00:38:04,534 --> 00:38:07,111
until the optimal moment to pull the trigger
728
00:38:07,111 --> 00:38:08,933
and release the arrow.
729
00:38:09,786 --> 00:38:11,755
The defense of Dover Castle
730
00:38:11,755 --> 00:38:15,091
relied on surveillance and the skill of crossbow snipers,
731
00:38:15,091 --> 00:38:17,314
hidden behind narrow arrow slits
732
00:38:17,314 --> 00:38:19,893
to attack any approaching enemy.
733
00:38:23,731 --> 00:38:26,964
(atmospheric music)
734
00:38:26,964 --> 00:38:29,993
Modern sniper weapons are similarly engineered
735
00:38:29,993 --> 00:38:32,918
for long range accuracy,
736
00:38:32,918 --> 00:38:35,089
reducing the enemy's combat ability
737
00:38:35,089 --> 00:38:38,273
by neutralizing high value targets.
738
00:38:39,943 --> 00:38:43,275
If you know about snipers, you know about their accuracy,
739
00:38:43,275 --> 00:38:44,457
the knowledge
740
00:38:44,457 --> 00:38:47,224
that they might be positioned in the war zone around you
741
00:38:47,224 --> 00:38:48,814
would be paralyzing,
742
00:38:48,814 --> 00:38:51,425
there's no sound, there's no warning,
743
00:38:51,425 --> 00:38:55,643
just suddenly the hit and your comrade is killed.
744
00:38:58,816 --> 00:39:01,683
Sudden death was something all too familiar
745
00:39:01,683 --> 00:39:03,515
to those attacking castles,
746
00:39:03,515 --> 00:39:06,616
but castle technology continued to evolve.
747
00:39:06,616 --> 00:39:09,376
In the final decades of the 13th century,
748
00:39:09,376 --> 00:39:11,186
a new battlefront opened up
749
00:39:11,186 --> 00:39:12,993
when successive English kings
750
00:39:12,993 --> 00:39:17,455
turned their attention to the conquest of Wales.
751
00:39:17,455 --> 00:39:18,915
It was an opportunity
752
00:39:18,915 --> 00:39:21,389
to combine the accumulated engineering ideas
753
00:39:21,389 --> 00:39:24,327
of the last 150 years
754
00:39:24,327 --> 00:39:27,313
to create the ultimate super castle.
755
00:39:28,860 --> 00:39:33,050
So the great Welsh castles of the 13th century
756
00:39:33,050 --> 00:39:37,219
are a sort of zenith in castle building design.
757
00:39:37,219 --> 00:39:40,240
Wales is famous for,
758
00:39:40,240 --> 00:39:42,752
arguably, having more castles per square mile
759
00:39:42,752 --> 00:39:45,309
than any other part of Europe.
760
00:39:45,309 --> 00:39:47,534
During the reign of King Henry III,
761
00:39:47,534 --> 00:39:50,800
one of the most powerful and ambitious barons in the land,
762
00:39:50,800 --> 00:39:52,090
was Gilbert de Clare.
763
00:39:52,090 --> 00:39:54,687
He was tasked with preventing South Wales
764
00:39:54,687 --> 00:39:57,670
falling into the hands of the Welsh leader,
765
00:39:57,670 --> 00:39:59,156
Llywelyn ap Gruffudd,
766
00:39:59,156 --> 00:40:01,453
who controlled most of Wales.
767
00:40:02,410 --> 00:40:03,243
De Clare decided
768
00:40:03,243 --> 00:40:05,391
the key to military domination of the region
769
00:40:05,391 --> 00:40:08,840
would be the construction of a giant castle,
770
00:40:08,840 --> 00:40:11,432
it would be a completely new kind of structure
771
00:40:11,432 --> 00:40:15,612
and it would be built at the mouth of the Rhymney Valley
772
00:40:15,612 --> 00:40:18,003
in a town named Caerphilly.
773
00:40:23,549 --> 00:40:26,383
Construction began in 1268,
774
00:40:27,248 --> 00:40:30,333
so what was so special about Gilbert's castle?
775
00:40:33,034 --> 00:40:34,498
Right from the beginning,
776
00:40:34,498 --> 00:40:38,140
Caerphilly changed the rules of medieval engineering.
777
00:40:38,140 --> 00:40:41,920
It's made up of a series of walls
778
00:40:41,920 --> 00:40:43,975
and gateways and towers,
779
00:40:43,975 --> 00:40:47,133
and each of those gateways has portcullises,
780
00:40:47,133 --> 00:40:50,618
and each of them is defensible in its own rights.
781
00:40:50,618 --> 00:40:52,805
It represented a huge leap forward
782
00:40:52,805 --> 00:40:55,120
in defensive capabilities.
783
00:40:55,120 --> 00:40:55,953
You've got the capacity
784
00:40:55,953 --> 00:40:58,917
to sustain multiple different attacks
785
00:40:58,917 --> 00:41:03,917
and to ensure that the castle never completely falls
786
00:41:03,918 --> 00:41:07,598
into the hands of those who are besieging it.
787
00:41:07,598 --> 00:41:09,286
So what were the challenges
788
00:41:09,286 --> 00:41:11,868
faced by potential attackers?
789
00:41:11,868 --> 00:41:14,400
The main castle sits on an island
790
00:41:14,400 --> 00:41:15,233
in the middle of a moat
791
00:41:15,233 --> 00:41:18,306
and that moat is retained by a north and south bank,
792
00:41:18,306 --> 00:41:19,733
but it's to the east
793
00:41:19,733 --> 00:41:23,927
where you have a fortified dam with gate houses.
794
00:41:23,927 --> 00:41:25,488
Unlike many castles,
795
00:41:25,488 --> 00:41:28,192
Caerphilly's moat couldn't easily be drained,
796
00:41:28,192 --> 00:41:32,039
so tunneling under its walls was impossible.
797
00:41:32,039 --> 00:41:34,710
It may seem that moats are a thing of the past,
798
00:41:34,710 --> 00:41:37,152
but, in fact, they're a defensive design classic
799
00:41:37,152 --> 00:41:39,093
still in use today.
800
00:41:42,593 --> 00:41:46,079
The moat is such a successful means of security
801
00:41:46,079 --> 00:41:48,577
that even the US Embassy in London,
802
00:41:48,577 --> 00:41:50,658
with its state of the art design,
803
00:41:50,658 --> 00:41:52,263
incorporates a moat.
804
00:41:53,270 --> 00:41:54,430
The Embassy
805
00:41:54,430 --> 00:41:56,595
is Central London's first new moated building
806
00:41:56,595 --> 00:41:58,653
since the Medieval Era.
807
00:42:00,130 --> 00:42:03,188
Intended as a defense against terror attack,
808
00:42:03,188 --> 00:42:04,918
it's said to be eight feet deep
809
00:42:04,918 --> 00:42:07,501
and wide enough to swallow any truck bomb
810
00:42:07,501 --> 00:42:09,553
charging towards the building.
811
00:42:14,687 --> 00:42:17,394
So given its highly effective moat system,
812
00:42:17,394 --> 00:42:18,530
was there any way
813
00:42:18,530 --> 00:42:21,669
an attacker could breach Caerphilly's walls?
814
00:42:21,669 --> 00:42:23,899
With the sheer amount of stonework you've got there,
815
00:42:23,899 --> 00:42:25,186
the sheer size of it,
816
00:42:25,186 --> 00:42:27,146
you've got walls within walls,
817
00:42:27,146 --> 00:42:30,434
walls studded with towers, seven gatehouses,
818
00:42:30,434 --> 00:42:33,310
all of those things on top of one another,
819
00:42:33,310 --> 00:42:36,873
it comes very close to being an impregnable fortress.
820
00:42:37,728 --> 00:42:39,949
I think only a madman
821
00:42:39,949 --> 00:42:42,565
would want to take on something like Caerphilly,
822
00:42:42,565 --> 00:42:44,125
the whole point of the construction
823
00:42:44,125 --> 00:42:46,384
of Caerphilly, in the first place,
824
00:42:46,384 --> 00:42:49,713
is simply to say don't even think about it.
825
00:42:50,836 --> 00:42:52,620
But within a century
826
00:42:52,620 --> 00:42:53,766
of Caerphilly's completion,
827
00:42:53,766 --> 00:42:56,861
a new weapon arrived on the battlefield,
828
00:42:56,861 --> 00:42:58,695
its incredible destructive power
829
00:42:58,695 --> 00:43:02,593
would signal the beginning of the end for the super castle.
830
00:43:10,949 --> 00:43:12,234
Throughout history,
831
00:43:12,234 --> 00:43:14,698
the invention of new ways to kill or destroy
832
00:43:14,698 --> 00:43:17,853
has abruptly changed the course of wars.
833
00:43:19,750 --> 00:43:21,089
In May, 1945,
834
00:43:21,089 --> 00:43:23,822
the Second World War came to an end in Europe
835
00:43:23,822 --> 00:43:27,082
with the surrender of German forces.
836
00:43:27,082 --> 00:43:28,754
However, in the Pacific,
837
00:43:28,754 --> 00:43:31,263
the fight with Japan was still raging,
838
00:43:32,696 --> 00:43:35,046
but one of the deadliest engineering breakthroughs
839
00:43:35,046 --> 00:43:38,173
of all time, was about to emerge.
840
00:43:39,571 --> 00:43:41,379
Codenamed the Manhattan Project,
841
00:43:41,379 --> 00:43:44,095
this was the top secret American-led effort
842
00:43:44,095 --> 00:43:47,968
to develop a functional atomic weapon.
843
00:43:47,968 --> 00:43:49,928
And in August, 1945,
844
00:43:49,928 --> 00:43:52,752
the devastating power of this new technology
845
00:43:52,752 --> 00:43:54,370
was made apparent
846
00:43:55,428 --> 00:43:59,623
when bombs were dropped on Hiroshima and Nagasaki.
847
00:44:00,551 --> 00:44:03,233
Within days, Japan surrendered.
848
00:44:06,247 --> 00:44:09,164
(whooshing sounds)
849
00:44:17,249 --> 00:44:18,603
The engineering development
850
00:44:18,603 --> 00:44:21,960
that finally brought the medieval super castle down to earth
851
00:44:23,320 --> 00:44:26,623
also turned out to be something explosive.
852
00:44:29,084 --> 00:44:30,491
The arrival of the cannon
853
00:44:30,491 --> 00:44:33,130
fundamentally changed the role of the castle,
854
00:44:33,130 --> 00:44:34,565
because those castle walls
855
00:44:34,565 --> 00:44:37,920
could not be protected from cannon fire.
856
00:44:37,920 --> 00:44:42,920
A cannon is very effective because you've got more power
857
00:44:43,961 --> 00:44:46,904
and you can direct the payload more accurately,
858
00:44:46,904 --> 00:44:49,447
so you can essentially hit your target
859
00:44:49,447 --> 00:44:54,447
with greater firepower and cause more damage accurately.
860
00:44:55,120 --> 00:44:58,150
The cannon consists of a strong metal tube
861
00:44:58,150 --> 00:44:59,693
with a plug at one end,
862
00:44:59,693 --> 00:45:03,313
a small hole for a fuse is drilled through the barrel,
863
00:45:04,560 --> 00:45:07,640
gunpowder is pushed down into the tube,
864
00:45:07,640 --> 00:45:09,076
then a solid ball is inserted
865
00:45:09,076 --> 00:45:10,670
so that gunpowder and ball
866
00:45:10,670 --> 00:45:13,023
are pressed against the plugged end.
867
00:45:13,910 --> 00:45:15,694
A fuse in the small hole is then lit
868
00:45:15,694 --> 00:45:17,653
to ignite the gunpowder.
869
00:45:19,033 --> 00:45:22,203
The resulting explosion shoots the ball out of the tube
870
00:45:22,203 --> 00:45:24,973
at high speed towards the target.
871
00:45:25,995 --> 00:45:27,549
The damage is done
872
00:45:27,549 --> 00:45:31,435
by the sheer power of the blunt force impact.
873
00:45:31,435 --> 00:45:32,580
To combat the cannon,
874
00:45:32,580 --> 00:45:36,519
castle design changed, walls were no longer built tall,
875
00:45:36,519 --> 00:45:38,247
but thick and squat,
876
00:45:38,247 --> 00:45:40,970
many were built of earth reinforced with stone
877
00:45:40,970 --> 00:45:44,026
to better absorb cannon shot.
878
00:45:44,026 --> 00:45:47,345
Castles were no longer the places of refuge and safety
879
00:45:47,345 --> 00:45:49,283
they once had been.
880
00:45:52,847 --> 00:45:56,159
So from the 15th century onwards,
881
00:45:56,159 --> 00:46:00,975
castles begin to experience a change in purpose
882
00:46:00,975 --> 00:46:02,841
and a change in design,
883
00:46:02,841 --> 00:46:07,841
and, partly, that's because models of warfare change,
884
00:46:08,309 --> 00:46:13,309
it becomes harder and harder and harder to defend castles
885
00:46:13,485 --> 00:46:17,768
against improved forms of attack.
886
00:46:17,768 --> 00:46:19,680
Castles gradually evolved
887
00:46:19,680 --> 00:46:21,862
from vital military defensive structures
888
00:46:21,862 --> 00:46:25,463
to symbols of power, pomp, and self-promotion.
889
00:46:26,785 --> 00:46:28,187
Developments in engineering
890
00:46:28,187 --> 00:46:31,100
now focused not so much on improving defenses,
891
00:46:31,100 --> 00:46:35,725
as improving the architecture, accommodation, and comfort.
892
00:46:35,725 --> 00:46:39,380
So what one sees is an evolution from the castle
893
00:46:39,380 --> 00:46:43,070
into the manor house, into the royal palace,
894
00:46:43,070 --> 00:46:45,573
into things that we much more obviously
895
00:46:45,573 --> 00:46:49,473
associate with courtly life, with aristocratic life.
896
00:46:50,376 --> 00:46:51,959
Grand old castles,
897
00:46:51,959 --> 00:46:53,555
like the famous Prague Castle,
898
00:46:53,555 --> 00:46:57,172
became centers of government or royal residences,
899
00:46:57,172 --> 00:46:59,654
such as Windsor.
900
00:46:59,654 --> 00:47:03,605
Even today, the super rich still enjoy building castles
901
00:47:03,605 --> 00:47:06,033
with varying degrees of irony.
902
00:47:08,867 --> 00:47:13,460
Sadly, war itself has not been banished to the past,
903
00:47:13,460 --> 00:47:16,832
defense of citizen's property and nations remains vital
904
00:47:16,832 --> 00:47:19,952
and now it's even closer to home.
905
00:47:19,952 --> 00:47:21,525
War is no longer confined
906
00:47:21,525 --> 00:47:24,307
to some sort of far distant battlefields,
907
00:47:24,307 --> 00:47:26,798
it's all around us all the time,
908
00:47:26,798 --> 00:47:30,945
we're increasingly living in an age of digital warfare.
909
00:47:30,945 --> 00:47:33,531
Battle lines are now drawn in cyberspace
910
00:47:33,531 --> 00:47:36,711
and the need for defense remains every bit as important
911
00:47:36,711 --> 00:47:39,175
as it was centuries ago.
912
00:47:39,175 --> 00:47:41,462
In this digital modern age,
913
00:47:41,462 --> 00:47:45,750
our most valuable resource is information and data.
914
00:47:45,750 --> 00:47:47,683
So the firewall on your computer
915
00:47:47,683 --> 00:47:52,683
acts rather like a curtain wall around a medieval castle.
916
00:47:53,918 --> 00:47:56,082
And just like in the medieval times,
917
00:47:56,082 --> 00:47:58,304
people are constantly trying to attack
918
00:47:58,304 --> 00:48:02,351
and steal the valuable resource behind that wall.
919
00:48:02,351 --> 00:48:04,768
(soft music)
920
00:48:10,459 --> 00:48:14,093
(atmospheric music)
921
00:48:14,093 --> 00:48:15,071
Castles were once
922
00:48:15,071 --> 00:48:17,082
the most powerful military bases
923
00:48:17,082 --> 00:48:18,844
in the Western world,
924
00:48:18,844 --> 00:48:23,588
the products of breathtaking feats of medieval engineering
925
00:48:23,588 --> 00:48:25,486
dominating the European landscape
926
00:48:25,486 --> 00:48:27,785
throughout the Middle Ages.
927
00:48:27,785 --> 00:48:31,581
New weapons were created to attempt their capture
928
00:48:31,581 --> 00:48:34,624
or to bring them crashing down,
929
00:48:34,624 --> 00:48:38,157
in turn, other engineers developed new defensive systems
930
00:48:38,157 --> 00:48:41,041
to thwart whatever was thrown at them.
931
00:48:41,041 --> 00:48:46,041
Castles became symbols of power and places of rebellion,
932
00:48:46,640 --> 00:48:49,312
ultimately, super castles couldn't compete
933
00:48:49,312 --> 00:48:51,162
with a form of firepower
934
00:48:51,162 --> 00:48:55,146
that could cause destruction with one blast.
935
00:48:55,146 --> 00:48:56,721
But thanks to the robust engineering
936
00:48:56,721 --> 00:48:58,620
behind their construction,
937
00:48:58,620 --> 00:49:01,936
many medieval castles are still with us today.
938
00:49:01,936 --> 00:49:03,504
They're now big business,
939
00:49:03,504 --> 00:49:05,731
allowing visitors to step back in time
940
00:49:05,731 --> 00:49:10,342
and marvel at the engineering prowess of a bygone age.
941
00:49:10,342 --> 00:49:11,880
I think there is something
942
00:49:11,880 --> 00:49:14,733
that speaks very immediately and directly to us,
943
00:49:14,733 --> 00:49:16,098
from childhood onwards,
944
00:49:16,098 --> 00:49:18,805
about living in a castle or defending a castle,
945
00:49:18,805 --> 00:49:20,173
or besieging a castle.
946
00:49:20,173 --> 00:49:21,006
So, for me,
947
00:49:21,006 --> 00:49:23,464
there's no quicker route back to the Middle Ages,
948
00:49:23,464 --> 00:49:26,522
that vanished world, than there is to go and visit a castle.
949
00:49:26,522 --> 00:49:29,272
(dramatic music)
73402
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