Original subtitles

- [Greg] We are surrounded by extraordinary feats

of engineering, constantly pushing the boundaries

of what's possible

- Without engineering, there'd be no modern world.

- [Greg] Gigantic cities, amazing infrastructure

and ingenious inventions.

- Engineering is the key to turn dreams into reality.

- [Greg] To reach these dizzying heights

today's technology relies on breakthroughs

made by ancient engineers.

- It's mind boggling how they did this.

- [Greg] How did early civilizations build

on such a scale?

- They raised the bar for construction

in a way that no one thought possible.

- The sheer engineering ability

that is in itself impressive.

- [Greg] By defying the known laws of physics

and daring to dream big.

They constructed wonders of the world

from gigantic pyramids to all inspiring temples

and mighty fortresses all with the simplest of tools.

- Can you imagine the skills people would have needed

to build like this?

- [Greg] Now it's possible to unearth the secrets

of the first engineers.

- They managed to construct edifices that has survived

the ravages of time.

- [Greg] And reveal how their genius

laid the foundations for everything we build today.

[dramatic music]

Standing proud over a city built in the desert,

the tallest structure in the world.

At just over 2,700 feet in height, the Burj Khalifa

in the United Arab Emirates embodies the financial power

of the modern Middle East, but it style also

reflects the region's rich cultural and religious history.

And it's not alone.

The design of many modern buildings is influenced

by their Islamic heritage.

Qatar's Al Thumama stadium, built for the 2022

soccer world cup represents the taqiyah,

a traditional woven cap worn by males

across the Arab world and beyond.

Morocco's Marrakesh Menara Airport,

clad in white aluminum panels feature stylized

Islamic ornamental designs.

And the design of the Petronas Towers in Kuala Lumpur,

Malaysia is based on the five pillars

of the Islamic religion.

The cross section of the towers reflects

the eight pointed star, a symbol of Islamic culture.

The engineering roots of these structures can be traced back

to what's known as Islam's golden age,

one of the greatest periods of scientific

innovation in human history.

- The modern world owes much to what we can consider

the golden age of Islam which lasts

from the eighth to the 13th century.

- There's a huge amount of innovation

in terms of architectural development.

- Which fundamentally changed the way

that people think in terms of geometry,

mathematics, astronomy, and education.

- [Greg] But what led to this new way of thinking

and ultimately to a revolution in Islamic engineering?

From the seventh and eighth century Islam spread outwards

from its birthplace in Arabia through the Middle East,

parts of Asia, North Africa and even into Spain.

The religion expanded through military conquest,

trade and pilgrimage.

- What was so special is that there was an introduction

of people from such a vast area

within one religious community.

People from North Africa and people

from the borders of China and from India

would all congregate, exchange ideas, philosophies, texts.

- [Greg] Islamic scholars were open-minded,

absorbing knowledge from all possible sources.

- They were not afraid to draw upon scholarly traditions

in earlier cultures and civilizations,

particularly from the Greek and Roman world on the one hand

and from the Persian and Indian worlds on the other.

- [Greg] They developed many of the most advanced ideas

of the age.

At this time Europe was reeling from the collapse

of the Roman empire.

The continent regressed into a period known

as the dark ages.

- This time in Europe, we can kind of think of

as a period of ignorance,

a period of oppression where we don't have

these same advances that we're seeing in the Muslim World.

- And one of the most notable of these Muslim scholars

was a man called Ismail al-Jazari.

He is seen today as the founder of mechanics.

- [Greg] Al-Jazari wrote an influential work

called the book of knowledge of ingenious

mechanical devices.

It featured meticulous diagrams and colorful illustrations.

- He designed objects that could appear

to be like mechanical robots of their time.

So they would be exquisite birds that look real

and then their wings would open up.

- [Greg] It led to the invention of mechanical clocks,

combination locks, and even the crank shaft.

The crank shaft helped improve water irrigation

and today is a central component of the automobile engine.

Although built before the Islamic golden era,

the waterwheels found in Hama, Syria benefited

from an Islamic mechanical innovation.

The flywheel helped watermills smooth out the delivery

of power, allowing some to lift as much as 660 gallons

of water per minute.

But mechanical devices weren't the only advances

being made in the Middle East at this time.

As the Islamic faith spread so too did the need

for worshipers to come together to pray.

And Islamic engineering prowess

would produce a new and important structure, the mosque.

- We can consider the mosque to be the architectural type

that most visually expresses Islam.

- They were statements of power as much as anything else.

They were designed to attract people to come towards them.

So you have these wonderful domes and these minarets

and also the noise of the call to prayer.

They were like a magnet for the local community

- [Greg] Beginning as humble courtyards

where the faithful could gather

they soon grew into incredible buildings,

housing thousands of worshipers.

But as numbers of the faithful swelled,

ever larger interiors were needed.

One vital engineering breakthrough would enable

Islamic engineers to build bigger.

- One of the most consistent features

in Islamic architecture is the dome.

- [Greg] It may be the mosque's defining feature,

but the dome was not originally an Islamic invention.

Islamic engineers drew on advances made

by an earlier empire, one renowned

for its magnificent buildings.

Grand and innovative structures dominated

the skyline of ancient Rome.

- The Romans were certainly one of the earliest people

to recognize the architectural potential of the dome

and it allowed them to build enormous internal spaces

without necessary supports.

- [Greg] The greatest example of a Roman dome

sits atop the Pantheon, a temple completed around 126 AD.

It weighs an astonishing 5,000 tons.

- It was the first time that the Romans

had actually worked out how to build a massive building

without any internal support.

It's mind-blowing even today.

- [Greg] Roman engineers realize that

by rotating and extending the arch element

they can create a strong three-dimensional shape, a dome.

- A dome is built by taking advantage

of the forces of compression, which point towards the top

of the dome and tension which point towards the bottom.

And the Romans use huge concrete pillars

around the bottom to absorb that tension.

- [Greg] Five and a half centuries

after the completion of the Pantheon,

the evolution of the Islamic dome began.

Following the successful Muslim assault on Jerusalem

in the seventh century, construction started on the Dome

of the Rock.

Its architecture was based on nearby Byzantine churches.

But this was the first major Muslim building intended

for public worship even though

it wasn't technically a mosque.

It's origins are shrouded in mystery.

- No one really knows why the Dome of the Rock was built

but it's of incredible spiritual

and emotional and political importance.

- [Greg] The building was constructed

at the end of the seventh century,

possibly with a dome being added to an existing structure.

There have been centuries of debate over its purpose.

- It was believed that this particular spot

was where Muhammad flew on a winged horse for Mecca

and ascended into heaven.

- [Greg] Other scholars believe

it's associated with Islamic and Byzantine beliefs

about judgment day, but there's no doubting

this structure's lasting significance.

- The Dome of the Rock is one of the most important

pilgrimage sites in the Muslim world.

And it's really important because it is one

of the earliest dated Muslim buildings.

- [Greg] The original dome collapsed

in an earthquake in 1015 and was rebuilt seven years later.

And down the years, it's had a number of upgrades.

In the 17th century under the Ottoman empire,

the exterior mosaics were replaced

with colored ceramic tiles.

The actual dome was most recently renovated in the 1990s

when it was coated with a layer of 24 karat gold.

Modern day mosques are adding spectacular shapes

to sometimes uniform cityscapes,

challenging engineers to stretch the limits of construction.

Completed in 1986, the Shah Faisal mosque

in Islamabad, Pakistan was designed

in the shape of a Bedouin tent.

The main structure of the building

is the central prayer hall, supported by four concrete

girders and covered in white marble.

The Sheik Zayed Grand Mosque in Abu Dhabi

in the United Arab Emirates features 82 domes.

One of these is the largest dome of its kind

in the world at nearly 280 feet high

with a diameter of 108 feet.

But breaking from the tradition of marble and stone

is the Kristal Mosque in Malaysia.

Opened in 2008, the mosque's exterior makes it unique;

a steel and glass structure giving rise

to its crystalline appearance.

Mosques must be capable of enduring the ravages of time

so modern engineers often turn to new materials

seeking the ideal combination of beauty and strength.

In 2004, a strong earthquake hit Morocco

in Northwest Africa killing more than 600 people.

So when engineers were commissioned to build a new mosque

in Casa Blanca tremors were very much on their mind.

Adding to the challenge, the structure was to be built

on the very edge of the Atlantic Ocean.

- It was a statement.

Islam has penetrated right to the edge

of the African continent.

But also there's a verse in the Koran that says

that the throne of Allah was built on the water.

And so here is a physical statement.

Look, this great most was constructed literally

on the edge of the Atlantic.

- [Greg] The building was constructed partially on land

and partly over the ocean.

To achieve this a platform was built to link the shore

with a natural rock outcrop where a swimming pool

had previously been located.

Two break waters were put in place

to protect the mosque from large waves.

Engineers also had to make the building quake proof.

So scientists got to work and developed a form

of concrete stronger than the ordinary type.

The highly resistant formulation they produced

had a fast setting time and was capable

of withstanding immense pressure.

The mosque's roof is covered with cast aluminum tiles,

stronger than the traditional ceramic type

but a quarter of their weight.

- The Hassan Mosque in Casablanca really is

a modern interpretation of the greatest

of the Moroccan mosques of the Marinid period

which is in the 12th and 13th centuries in Moroccan history.

- [Greg] The structure also features another

cutting edge innovation.

- Something that brings it into the 21st century,

the large laser that shines directly towards Mecca.

- [Greg] The Hassan II Mosque opened in 1993.

It took seven years to construct, employing 35,000 workers

laboring over 50 million hours.

But such modern day marvels are reliant

upon an Islamic engineering innovation

from the ancient world.

Lying in the desert around 100 miles Southwest of Baghdad

is the Palace of Akkadian.

It's thought to have been built under an early

Islamic dynasty named the Abbasid Caliphate,

a line of rulers descended from the uncle

of the prophet Muhammad.

- The palace of Akkadian is one of the best preserved

early Abbasid's palaces, but it's one

on which we have practically the least information written.

We can date it to around the year 778.

- [Greg] But what made this palace different

to others that had gone before?

One reason lies within the building,

an Islamic engineering development

that went on to have a major influence on medieval Europe.

For centuries engineers had made use

of the semicircular arch.

- The purpose of an arch in a building is to be able

to create space or an opening

so that you distribute the load around the arch

which means you've got free space underneath.

In an arch. the load is distributed evenly around the arch

in compression, but that creates a big outward push force

which has to be resisted by the walls

that are holding the arch in shape.

- They have a huge advantage over horizontal beams

or lintels because they can carry so much more weight.

- [Greg] The force is generated by semicircular arches

and strong thick supporting walls were a necessity.

But at the palace of Akkadian came a breakthrough.

The pointed arch, a great leap forward

from the heavy Roman arch.

- What a pointed arch enables you to do is to get higher.

It can bear the same load, but it can work its way up higher

and create a larger opening as well,

which allows more light in.

- [Greg] The pointed arch distributes weight downwards,

not sideways.

So this engineering breakthrough also meant heavy walls

were no longer necessary.

- What the pointed arch allows you to do

is build buildings of unprecedented height and scale.

Because while a Roman arch, a semicircular arch

is very limited in how far you can actually draw your walls

apart before it becomes structurally unsound,

a pointed arch theoretically you can just keep going up

until you get to the top.

- [Greg] Eventually, pointed arches would also

become a common feature of European churches

- Without this engineering design development

Europe would not have these amazing cathedrals

that we have today.

The likes of Notre Dame, Westminster Abbey.

- [Greg] Even today, engineers are still pushing

arch design to new heights.

In the late 1940s, the city of St. Louis, Missouri

sought to commemorate its role in the westward expansion

of the United States.

To do so it was decided to build

a spectacular public monument.

The winning design was picked in a competition,

a 630 foot arch, a symbolic gateway to the West.

- It's huge challenges is of how on earth

do you construct something that is curving up

like nearly 200 meters high

and stop it falling over and then allow people to go up

inside the middle of it as well.

So it's very challenging project.

- [Greg] Construction of the arch required

some highly sophisticated engineering.

It drew upon lessons first learned

back in the ancient world.

The Taq Kasra monument built around the third century

is a testament to Persian engineering skills.

Located in Iraq the arch was once part

of an imperial palace complex.

To enable it to support its own weight,

engineer's use to design known as the catenary arch.

- A catenary arch, if you imagine you've got a necklace

or a chain and you hold it at the edges

it's the natural shape that would form under gravity

and self weight of the material itself.

So you get this perfect curve.

And if you flip that up the exact same shape

is what a catenary arch shape is.

- [Greg] For the 20th century St. Louis Gateway

engineers started with the structures two legs.

Each leg is embedded in concrete foundations

44 feet thick and 60 feet deep.

- The engineers and builders constructing

the Gateway Arch had to have extreme precision

because even if they made an error of less than

half a millimeter or 1/64 of an inch at the base points

when they started building it wouldn't have met at the top.

- [Greg] The main structure was erected section

by section, 142 elements in total.

Each resembled a steel triangle narrowing towards the top.

- The Gateway Arch has got a thin stainless steel

outer skin and it's also got a layer of steel

and concrete inside it to give it strength and rigidity.

But a lot of it is actually just air

so it makes it lights inside.

- [Greg] The arch was completed in October, 1965,

taking just over 32 months to construct.

Even today it remains the tallest arch in the world.

The desire to build the world's tallest

has long been a driving force in engineering design,

but in the Islamic world, building high was important

for one very specific reason.

[prayer hums]

Fundamental to Islam is the religious duty of daily prayer.

- In Islam there are five particular times of day

at which Muslims are supposed to pray

and this is one of the five pillars of Islam,

these five daily prayers, which are to be undertaken.

- The way that Muslims know when it's the time to pray

is by symbol as in to call out and say,

come, now is the time to pray to God.

[melancholic music]

- [Greg] But ancient Islamic engineers

had to find a way to ensure the call to prayer

could be heard as widely as possible.

With pointed arches enabling the construction

of tall towers the solution was the minaret.

- The minaret is essentially a tower.

Minaret means light, it's a place of light.

They do function as landlocked lighthouses.

It's something that when you're traveling at night

this series of minarets in towns and across the landscape

provides a way of traveling.

But their primary function is for somewhere

for the person to make the call to prayer from.

People can hear that voice above the melee below

and know that it was time to go and pray.

- [Greg] Minarets come in many shapes and sizes.

- So we, first of all, have these spiral shaped minarets

like at Samarra.

And then the form of the minaret is transformed

particularly in Central Asia into the sort of

tower minarets, the slender high towers

elaborately decorated.

That is what we now see as the sort of standard shape

of the minaret.

- [Greg] Although relatively straightforward

to construct many these ancient towers

are now under threat from the modern world.

The Al Khulafa Mosque in Baghdad was built in 1279

and it's minaret stands 112 feet tall.

But in recent years it has experienced

an engineering failure.

- Basically it's starting to tilt.

- [Greg] The mosque is better known by locals

as al'ahdab, the hunchback due to its minaret's

precarious angle.

A 2013 study revealed it had tilted four feet off center

and was still moving approximately 0.19 inches per month.

Geophysical surveys were undertaken to identify the cause.

- They discovered that the reason why the foundations

are being undermined was because wastewater

and sewage from a nearby municipality pump

was being pumped through the ground underneath the building.

And that weakened the structure of the ground

that it was based on and therefore led

to it starting to tilt.

- [Greg] UNESCO and the Iraqi government

are developing plans to prevent the minaret's collapse.

Islamic minarets had to be taller than surrounding buildings

as sound waves travel further with no obstructions.

The same principle even applies to the very latest

communication technology of today.

As buildings have grown ever taller, modern radio towers

also have to reach higher and higher.

Whether they're for TV, radio, or cell phones,

communication towers have become iconic landmarks.

The range of a transmission is determined

in part by the height of the towers.

The largest have a reach of up to 60 to 70 miles,

depending on topography.

From Toronto to Moscow and Shanghai,

these are among the tallest structures ever built.

And in Tokyo, engineer's plan to construct a tower higher

than any that had gone before.

It called for some innovative technology

as this city is in the middle of a major earthquake zone.

The new 2,080 foot tall structure would be

called the Tokyo Skytree.

To protect it from earth tremors it's design

is underpinned by surprisingly ancient technology.

Engineers drew inspiration from a five story pagoda

called the Horyu-ji Temple.

Built more than 1,300 years ago,

it's one of the world's oldest wooden buildingS.

Despite countless earthquakes over the centuries,

the structure has never collapsed.

- These pagodas are unbelievably resistant

to earthquake forces.

Nobody really knows exactly why, but a thing called

a shinbashira, which is a core that goes

in the center of the pagoda that essentially acts

like a pendulum to dampen the horizontal force

of an earthquake is probably one of the reasons

why these are so sturdy and withstand

these incredible earthquakes.

- [Greg] During an earth tremor, the shinbashira acts

like a counterbalance within the temple.

This diminishes the force of the shock waves

threatening to destroy it.

Emulating this design within the center of the Skytree,

engineers built a hollow core.

It contains a shinbashira running the length

of the structure, connected to the steel frame

of the building by hydraulic dampeners.

- The outer structure of the Skytree

is essentially protected from the full force

of the earthquake because this central core pillar

provides a bit of a dampening effect.

- [Greg] But even as it was under construction

the Skytree was put to the test.

March, 2011 saw the largest earthquake ever recorded

in Japan.

It measured 9.0 on the Richter scale

and the epicenter was around 230 miles Northeast of Tokyo.

Severe tremors impacted the city causing many

skyscrapers to shake violently.

But what about the unfinished Skytree?

- They were very lucky because the shinbashira

was already in place and it did its job

and the Skytree at that level of construction

still stayed in place.

- [Greg] Before it was even completed,

the Skytree had earned its place in engineering history.

Back in the eighth, century political power

and military might saw Islam spread far

beyond the Middle East.

In 711, crossing the sea from North Africa,

a Muslim army landed on what was to become Gibraltar.

Over the next seven years it conquered most

of the Iberian Peninsula, modern day Spain and Portugal.

- The Muslim armies were very much a land-based force.

They're mainly a mounted archery force.

So they were able to fire from horseback.

This is what really made the European army's struggle with.

They weren't used to people galloping and firing at them.

- [Greg] But to secure the lands they invaded

the Islamic forces relied on advanced

engineering techniques.

As a result Southern Spain has one of the largest

concentrations of medieval fortresses in all of Europe.

One of the best preserved and oldest overlooks

the town of Banos De La Encina, the Burgalimar Castle.

Its appearance is striking, dominating the landscape

with its vivid reddish color.

This remarkable defensive structure also contains

an engineering secret built into its very fabric.

- The walls are incredible to look at

and there are 15 towers which are incorporated

into the exterior.

So it's a very defensive looking building.

When you look at this castle it looks like it's built

of stone, but it's actually built of an Adobe like material

of Arab origin.

- [Greg] Adobe is made up of materials

that bind together under compression.

At this time, Islamic builders were also

using another similar construction technique

known as rammed earth.

- Rammed earth buildings are created

by getting a selection of aggregates.

So clay, gravel, silt, and ramming it into a structure

which has been built by wooden frames.

And once it's all rammed into place

those frames are removed leaving

a very, very substantial wall.

- [Greg] Although this method can be labor intensive

it has a very low environmental impact.

It makes use of locally available material rather

than transporting stone from far away.

Rammed earth construction techniques date back

thousands of years but their use increased

with the expansion of Islam.

Invading Islamic armies use this form

of engineering across North Africa and into Europe,

building large fortresses and city walls as they went.

And in the modern world rammed earth buildings

are having a Renaissance.

- Rammed earth, it doesn't exactly scream innovation

but yet it's coming back as a building method

because of its structural properties

and other useful properties like its thermal mass

for controlling temperature.

It can control room humidity at a perfect 40 to 60 degrees.

- [Greg] Rammed earth construction techniques

are also highly energy efficient.

- You don't need any processing at all.

It doesn't use cement.

Doesn't use energy really apart from the energy that's

associated with moving the earth and tapping it down.

- [Greg] As the world becomes ever more eco aware

demand for renewable energy intensifies.

Power from the sun, the oceans and wind.

And there's one settlement in the Middle East

that has been taking advantage of the wind

for the last 1,000 years.

Located on the barren and wind swept planes

of Northeastern Iran near the Afghan border

is the small village of Nashtifan

which is keeping an ancient tradition alive.

Perched high up on a hill, overlooking the settlement,

some very strange contraptions are visible.

They have been cleverly engineered to harness

the power of nature.

- In Nashtifan there are windmills

which are still in use today which are

an extraordinary survival, both of Islamic engineers,

but also going back probably into a pre-Islamic

Persian period.

And these are not like normal windmills,

but are basically vertical windmills mounted on a small,

low cliff to catch the wind.

- [Greg] As with the more famous European

windmill design, these pioneering devices

were constructed to grind wheat into flour.

But the design of these windmills are thought

to date back to between the sixth and 10th centuries,

long before they were introduced elsewhere.

- The tradition is that these windmills were invented

by a Persian slave working for one of the early

Umar caliphs claim that, you know

these were the most extraordinary invention.

- [Greg] Each windmill is about 65 feet tall

comprising eight chambers, and each chamber houses

six blades.

- There was a vertical shaft that goes down

to a subterranean mill in which it is connected

to two millstones, which are grinding the core.

And because the wind is so strong

in this particular parts of Iran

it's sufficient to efficiently keep these mills going

over long periods of time.

- [Greg] Wind power is more important than ever

and in recent years engineers have made great strides

in turning this elemental force into electricity.

There are now over 340,000 wind turbines across the planet.

From the California deserts to the green hills of Scotland

and giant offshore farms.

At their heart some simple but effective engineering.

- The idea of a wind turbine is basically

that the wind moving causes a blade to turn around

which drives the generator and produces electricity.

- [Greg] The majority of wind turbines fall

into two basic categories.

- A horizontal axis turbine which has a blade

that goes like this.

It looks like a windmill blade.

And another one which is called a vertical axis turbine

which they kind of look like spirals

and they spin round in that direction, so vertical axis.

- [Greg] Most commonly turbines have three blades

and operate up-wind.

The turbine pivots at the top of the tower

and the blades face into the wind.

- The great benefit of wind turbines especially

when you use lots of them is that we prevent

carbon dioxide being emitted and currently we're saving

hundreds of millions of tons of carbon dioxide

by using wind turbines.

- [Greg] Wind turbines aren't without opponents.

Some believe they can harm wildlife

or spoil natural landscape.

Despite many years of innovation,

by the 13th century the Islamic golden age

was nearing its end.

With the Mongolian empire expanding to the west,

Baghdad was sacked in 1258 ushering in a period of decline.

But other Islamic empires were emerging.

One rising dynasty would help turn India

into an economic and military powerhouse.

- The Mughal empire was founded in 1526

by the Timur prince named Babur.

- [Greg] Babur invaded India from his stronghold

in Kabul, now the capital of Afghanistan.

- He's a fascinating character

because he was related not just to one famous warrior,

but to two.

He was related to Timur, otherwise known

as Tamerlane the Great and also to Genghis Khan.

So conquering was in his DNA.

- [Greg] The Mughals were ambitious,

hatching grand engineering and military plans.

Among countless projects they transformed Jaigarh Fort,

136 miles Southwest of Delhi into one of the greatest

cannon foundries in the world.

The fort was built with thick walls of red sandstone

and spread over a vast area nearly two miles long

by half a mile wide.

It was constructed in a region with an abundance

of iron ore mines, source of the raw material for cannon.

Mughal engineers also devised an ingenious wind tunnel

on an unprecedented scale.

Its purpose was to draw air from the high mountains

for use in heating furnaces.

- You needed an exceptionally high temperature

to create these cannons.

And so the furnaces apparently reached temperatures

up to 2,400 degrees Fahrenheit or a 1315 Celsius.

So really, really intense heat to create these.

- [Greg] The cannon produced here were big,

including one of the largest in the world.

This 50 ton 20 foot monster rests

on two massive wheels nine feet in diameter.

Never used in war, the giant weapon

was only once tested fired.

[gunshot]

As well as building on all the great learnings

of Islamic engineering, the Mughal empire

would also introduce a new focus on architectural beauty.

Under various emperors, they embarked on a series

of epic building projects, constructing lavish palaces

and mosques the likes of which had never been seen before.

It culminated in one of the most iconic

and famous buildings on the planet, the Taj Mahal.

Photographed millions of times, visited by people

from across the world.

Superstars, world leaders and royalty all have marveled

in awe at its splendor.

- The Taj Mahal is one of the most iconic buildings

in the world.

Probably one of the most recognizable.

It's become a symbol of the country of India.

It is overwhelming.

It is a building that awes you.

- [Greg] The Taj Mahal has been voted

one of the new seven wonders of the world.

- The Taj Mahal is a truly staggering creation.

It's particularly wonderful because it seems

to almost come alive when you look at it.

- The engineering of the Taj Mahal itself

is just incredible.

But the beauty and the serenity as you're walking

around it is the thing that almost touches your soul.

- [Greg] However, this masterpiece of art

and engineering is neither a palace nor a mosque.

- The Taj Mahal was built by the fifth Mughal emperor

Shah Jahan, who reigned from 1628 to 1658

and he built it as a mausoleum

for his favorite wife Mumtaz Mahal.

She died giving birth to their 14th child

and a year later he started construction

on this amazing monument to her.

- [Greg] Built on the banks of the Yamuna river

in the Indian city of Agra around 130 miles Southeast

of New Delhi, the Taj Mahal and its gardens

cover an area of nearly 17 hectares.

- We can certainly consider the Taj Mahal

to be the Zenith of Mughal architecture.

Taj Mahal translates as the crown of the palace.

- The Taj Mahal is an engineering marvel.

It's absolutely extraordinary.

Everything in it is perfect.

It's been conceived with a plan, it's all symmetrical

and it is built with the most remarkable craftsmanship

in history.

- [Greg] It was built over a period of 22 years

employing 20,000 workers.

28 types of precious and semiprecious stones

were used in its construction.

- It costs a phenomenal sum of money.

Something like 32 million rupees

which in modern terms is a billion dollars.

- [Greg] But this famous white marble mausoleum

is not all that it seems.

- So when we at the Taj Mahal, we are overwhelmed

with this aesthetic of white marble,

which, you know gleams at certain times of the day

but the building is not actually constructed of marble.

- [Greg] Even the grandest buildings

of this period were constructed with red sandstone.

This would then be hidden by an outer skin

of finer material.

- So with the Taj Mahal, it's of stone building,

but covered in just sheets and slabs

of this amazing white marble.

- [Greg] But the Taj also used innovative engineering

techniques far ahead of their time.

A recent scientific survey revealed that the 16th century

designers may have anticipated some potential disasters.

- The four towers which frame the mausoleum structure

were built to just ever so slightly lean away

from the mausoleum.

So if for some reason a minaret was to collapse

it would not fall in the direction of the mausoleum

but would fall away from it.

- [Greg] The monument's location on the banks

of the Yamuna river also presented a major challenge

to construction engineers.

- The ground around there is soft clay

and silt is really, really poor ground.

And the Taj Mahal is a very dense, huge stone building

which is very heavy.

And so the foundation construction to stop it just sinking

into the ground was a huge challenge.

- The foundations of the Taj Mahal were built

using something called a well foundations.

- [Greg] Workers first sunk deep shafts

right down to water level.

These were lined with ebony which wouldn't rot.

The gaps were then crammed full of stones

with arches built above.

For nearly 400 years these foundations

have prevented the structure from sinking

into the soft riverbank.

- So the Taj Mahal is a bit like an iceberg.

What you see is just at the top

but there is an immense structure beneath the surface.

- [Greg] However, the land directly across the river

from the Taj Mahal is the site of further mystery.

Legend tells that following completion of the mausoleum

to his wife, Shah Jahan planned to build

an identical monument for himself.

Only this mirror image would be in black marble

instead of white.

- It's a wonderful story and it creates

such an evocative image but there is no

archeological evidence to indicate

that this was ever actually intended.

What actually happened is when Shah Jahan died

he was taken very unceremoniously at night to the Taj Mahal

and he was buried there as well.

- [Greg] Shah Jahan died in 1666

and within a few decades the Mughal empire

was sinking into decline.

But the innovation and invention of the Mughals

and at the golden age of Islam

are still influencing engineers to this day.

Throughout the world new Islamic structures

celebrate the past while also looking towards the future.

Sometimes in the most outlandish

and creative ways imaginable.

Located in the United Arab Emirates

and inspired by the domed roofs of ancient Islam

is the Louvre Abu Dhabi.

It costs over $100 million to construct

but its name came with an even higher price tag.

- They actually had to pay the French government

$500 million for the right to use the name of Louvre.

- [Greg] This structure's engineering

took his Islamic dome design to new heights.

Its architect had a vision of a dome that would appear

to float with as few support structures as possible

to avoid interrupting the flow of the building

- To get this design right was a significant challenge.

They kept having to go back to the drawing board.

23 times they had to remodel this in order

to get the design that worked with the lights

and with that feel of space and serenity just perfect.

- [Greg] Four concrete towers were put in place

to support the dome's weight.

They were ingeniously hidden within the building structure,

vital in creating the illusion of a floating dome.

But engineers also had to overcome another problem.

During the heat of the day the dome might expand

by a number of inches before contracting

in the cool of the night.

- Essentially the building is breathing in and out.

- [Greg] The ingenious solution was to fit each support

with huge six ton spiritual bearings,

ordinarily used on bridges.

- Is a kind of curved sliding plates

which sit on top of the supports.

And as the roof expands, it slides over these bearings.

And as the roof contracts, it slides back over.

- [Greg] Many modern buildings

are designed to be weatherproof, shockproof and fireproof.

They're engineered to take all that

the elements can throw at them.

But lacking this protection, one of the world's

greatest Islamic structures is now under threat.

- The Taj Mahal is certainly losing its looks at the moment.

The city where it's built is one of the most polluted

on earth.

The color of the white marble is changing

from white to yellow.

There are cracks appearing in the building itself

and the foundations are now very, very insecure.

- [Greg] The upper parts of the minarets

are said to be on the verge of collapse.

When high winds struck the Taj in 2018,

two pillars on an outer building, fell to the ground.

Engineers are racing to understand why

the structure is degrading.

- It's a particular problem with the river

near which the Taj Mahal has been built.

- [Greg] When the Taj Mahal was constructed,

the river Yamuna was an important route

for business and travel.

But as India's population grew and industries flourished,

dams were built on the river reducing its flow.

- And as the water level has fallen

that means that the foundations are no longer

always wet, but they need to remain wet

to retain their structural integrity.

If the foundations of a Taj Mahal become too dry

they will crack and they will not be able to support

this enormous building on top of them.

- [Greg] But it's not just the foundations.

- You've got local air conditions that are actually

corrosive to the building structure itself.

- [Greg] Measures have been taken to help preserve

this great Islamic monument.

Vehicles are now banned from within 1,640 feet of the Taj.

- The government has prevented local industry

from producing the toxic gases in the area,

but more needs to be done to preserve

the building structure itself.

- [Greg] The Taj Mahal is not only a landmark of India,

it's also a world heritage site.

- When we look at the Taj Mahal today,

we're looking at a structure and a complex

that was formulated and built at the height

of one of the greatest empires of the early modern era.

And it's still here.

It's still standing.

So it's a testament to the engineers who worked on it.

It's testament to the countless nameless who worked on it

and speaks to the incredible initiative of these people

at the time.

It's really a wonder of architecture.

It's a wonder of engineering and you know, it's a marvel.

- The Taj Mahal is so important to us

because it's such a powerful reminder

of what could be achieved back hundreds of years ago,

back in the 16th century.

- [Greg] The Taj Mahal is testament

to the incredible Islamic engineers of the past.

And today across the Islamic world

new buildings continue to emerge from this tradition.

Completed in 2010, the Burj Khalifa

in the United Arab Emirates became the tallest building

in the world and it's design was inspired

by a ninth century mosque.

Completed in 851, The great mosque of Samarra in Iraq

was for a long time the largest mosque in the world.

Just like the mosque, the Burj Khalifa

is built to a spiral pattern design

but its Islamic influence runs even deeper.

The Burj Khalifa was constructed using a 20th century

technique developed by an Islamic engineer.

- Originally skyscrapers are built with steel structure

so that you've got essentially pillars, columns

that are supporting the weight of the building

as it goes up.

- [Greg] All that was set to change in the 1960s.

- A Muslim engineer Fazlur Rahman Khan

came up with an idea that revolutionized

how skyscrapers are built.

- [Greg] Khan was described as the Einstein

of structural engineering.

Instead of rigid steel frames, his brilliant idea

was to use a tubular design.

It forever changed the way tall buildings were constructed.

- Fazlur Khan came up with a system

where he effectively bundled the structure together

in a series of tubes, which were tied together

which allow buildings to go taller

and stay rigid and remain slender.

- [Greg] This engineering technique

meant that skyscrapers such as the Sears Willis Tower

in Chicago no longer had to stick to a dull boxy form.

- So the outside is actually the structural part

of the building that holds the strength

of the materials itself.

So it means that you can build high

because the taller you build the more structural stability

that you've got supported by the skin

of the building itself.

- [Greg] Khan's innovation may not have come in Islam's

golden age but it has allowed buildings in cities

throughout the world to reach ever higher.

Since Islam seventh century origins in the Middle East,

the creativity of its engineers led

to countless innovations.

During the golden age, their work touched all aspects

of life.

The legacy of their early buildings and innovations

has influenced generations of engineers.

They also created one of the most beautiful structures

on the planet and their breakthroughs helped the world

build ever bigger and ever taller,

changing cityscapes forever.

[dramatic music]