Original subtitles

Narrator: The lighthouse of alexandria --

One of the ancient Seven wonders.

The world's tallest stone tower For over 1,500 years,

It's an engineering marvel.

Build a skyscraper from stone -- You're crazy, you know?

We don't do that.

Narrator: Once a shining beacon to the Greatest city in ancient egypt,

Today, the lighthouse Is lost in time.

Khalil: we are actually Discovering for the first time

One of the wonders Of ancient world.

Narrator: Now investigators use innovative

Underwater digital-scanning Technology

To uncover the hidden secrets Of the vanished lighthouse.

They re-create ancient Engineering techniques

To reveal the lost skills of The civilization that built it.

Yeah, it's burning! It's burning!

Hee-hee! We set fire to it.

Narrator: to solve the mysteries Of this ancient wonder,

We'll unearth its sunken ruins,

We'll resurrect An ancient weapon of war,

And rediscover Long-forgotten technology

To rebuild The lighthouse of alexandria.

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Captions paid for by Discovery communications

Alexandria -- the last of Ancient egypt's capitals

And still the largest city On the mediterranean.

Legend has it that in 280 b.C.,

It's home to A mighty mega structure

That no other ancient city Can build.

At the entrance To alexandria's port

Stands the tallest tower In the world --

An egyptian skyscraper.

Immense bronze tritons, Greek gods,

Keep watch over The streets below

While mirrors beam A blazing light across the sea,

Making alexandria visible to Ships still a day's sail away.

Rumors even tell of a deadly Weapon at the tower's summit.

Why do the egyptians build This legendary lighthouse,

And what does it Really look like?

♪♪

The lighthouse of alexandria Stands for more than 1,500 years

Until 1303, When an earthquake and tsunami

Send it crashing into the sea.

Today, the lighthouse,

Along with almost all The ancient city,

Is gone.

Emad khalil is A marine archaeologist.

He spent the last 25 years Tracking down

Ancient alexandria's Lost secrets.

This is the ideal place to start Hunting for the lighthouse,

Mainly because of the material We have here.

Narrator: emad explores The citadel of qaitbay

On alexandria's waterfront.

Khalil: well, this would be The most durable material.

It will withstand the weather And the salt and so on,

And so this has probably came From a maritime structure.

Narrator: it turns out

Parts of alexandria's Fabled lighthouse survive.

Khalil: this fortress of qaitbay Was built

Using some of the blocks That existed in the lighthouse.

Narrator: and beneath the blocks Hides another clue.

Inside the fort stands A sacred mosque.

It should be facing mecca To the southeast,

But this mosque faces north, Towards the sea,

A clue that it stands on The old lighthouse foundations.

On the roof of the mosque Is a strange octagonal opening.

Can this help emad work out

What the ancient lighthouse Looks like?

♪♪

Khalil: the structure of This mosque is quite typical

Until you start looking up, And this is very unusual.

It's very unusual to have A square minaret, basically,

And part of it is octagonal,

And then another part Is cylindrical.

That doesn't happen In islamic architecture.

Narrator: emad is convinced The mosque's distinctive design,

A square base topped With an octagon and a circle,

Copies the shape Of the lighthouse.

That's because 30 miles West of alexandria,

There's an ancient structure That follows this blueprint --

Abusir lighthouse.

It stands guard over An ancient necropolis.

So what we have here, basically, Is a typical hellenistic tomb --

An altar in the middle And couches --

Two couches, one on each side -- To be used by visitors,

And then we have The burial chamber.

You'll still see The remains and the bones

And the remains of the deceased.

Narrator: on some of the walls, Snake carvings offer protection

To the spirits of the dead, Typical of a greek-style burial.

Khalil: all around us, There are plenty of them.

There are, I think, Over 13 of them,

Very much the same design -- Greek tombs.

And this is a building which was Built during the same period,

During the same era, In the shape of a lighthouse.

Narrator: emad thinks The builders of these tombs

And the lighthouse That guards them

Take inspiration from The lighthouse of alexandria.

Khalil: It's an evidence.

It gives us indication That this is the shape

Of the original Lighthouse of alexandria.

Narrator: abusir lighthouse is A miniature copy

Of the ancient wonder.

♪♪

Only a few precious images

Of the lighthouse Of alexandria survive,

And the lighthouse at abusir

Confirms they offer A true glimpse

Of a lost wonder Of the ancient world.

Khalil: so the builders of this Were actually able to see

The original lighthouse Of alexandria

And copy the design Into this structure.

The ancient alexandria Lighthouse had three levels --

A square one, an octagonal one, And a cylindrical one

Very much similar To this monument we have here.

Narrator: the lighthouse Of abusir solves the mystery

Of the lighthouse Of alexandria's appearance.

It's now clear That it's a huge building

With a distinctive Three-level design,

But the height Of this ancient wonder

Is still shrouded in legend.

Some say the lighthouse Is so tall

That a stone Falling from its summit

Would take two days To hit the ground...

...Others that sailors could see The lighthouse beacon

Up to 300 miles out to sea.

Emad's challenge is to separate Fact from fiction.

Can he use archaeological Evidence to work out

How high the lighthouse of Alexandria soars into the sky?

[ stone crumbling ]

[ stone crumbling ]

Narrator: The lighthouse of alexandria,

One of the seven wonders Of the ancient world,

Climbs into the sky Like no other ancient building,

But just how tall Does the lighthouse tower?

Archaeologist emad khalil Believes

Alexandria's eastern harbor Holds the answer.

In 1303, an earthquake destroys Most of the lighthouse.

But its fallen remains Still rest on the sea floor.

What we have here is 13,000 square meters

Of remains underwater.

Narrator: Scattered across the seabed

Lie thousands of stone blocks...

...Among them, Massive monoliths...

...The largest weighing Over 70 tons.

The huge blocks piece together To form the lighthouse door,

A towering gate Over 40 feet high

And 16 feet across.

Flanking the entrance -- Colossal statues

Of egypt's king and queen, Five times taller than a human.

Can this huge door reveal the True height of the lighthouse?

♪♪

Khalil: It's a huge puzzle, basically,

And you want to put it back Together without a reference,

Without a picture To base your reconstruction on,

And this is the main challenge Of the site.

Narrator: this mammoth block is A crucial piece of the puzzle.

It will help emad calculate The lighthouse height.

This huge object, which is about 70 tons in weight,

Is the right side of the main Entrance of the lighthouse,

The right side of the doorway Of the lighthouse.

The angle here is where The wooden door would have fit.

Narrator: working out the height Of the lighthouse

From its broken pieces is tough.

Luckily, an arab writer From the 14th century

Offers a helping hand.

He records some of the only Reliable measurements

Of the lighthouse.

He measures the dimensions Of its base

And the width of the doorframe

In an ancient unit Called the span.

Looking at width of the doorway, Of this side of the doorway,

We have 6-feet-10,

And now we can calculate The actual evidence

To the literary sources,

Which mention that the Measurement would be 10 spans.

Narrator: this recovered block Allows emad to establish

That 1 alexandrian span Equals 8 inches.

We can start rebuilding not just The dimensions of the lighthouse

But the entire complex Of the lighthouse.

Narrator: Translating the ancient Measurements reveals

That the lighthouse stands On a 100-foot square base.

This gives emad a starting point

To estimate The building's height.

He combines greek principles Of proportion and imagery

From ancient coins To finally get his result.

We think that it was 300 feet In height, and so it --

Basically, it was An ancient skyscraper.

Nothing like this In the ancient world.

Narrator: the lighthouse Of alexandria soars higher

Than any other stone tower In the ancient world

And even the first 20th-century skyscrapers.

Why does it need To stand so tall?

[ stone crumbling ]

[ stone crumbling ]

Narrator: The lighthouse of alexandria,

One of the seven wonders Of the ancient world --

At over 300 feet, it stands Taller than any stone tower

Until the 20th century.

A lighthouse must shine far And bright

To warn sailors away From dangerous waters,

But even the tallest lighthouse In america,

Cape hatteras light In north carolina,

Stands just over 200 feet tall.

So why is the ancient Lighthouse of alexandria

Over 100 feet taller?

Could this be So it can guide ships along

The treacherous waters Leading up to alexandria?

A clue lies 130 miles west Of alexandria,

Off egypt's mediterranean coast At marsa bagoush.

Beneath the calm surface Lurk deadly rocks

And shifting sandbars The size of houses.

Half buried in the sand

Lie the shattered remains Of countless amphorae,

Ancient clay pots For carrying wine and oil.

These shards span 2,000 years of history

And hint this bay Is a ship's graveyard.

Is the colossal Lighthouse at alexandria

Built to prevent Endless shipwrecks?

Archaeologist emad khalil And his team

Dive this site to investigate

If these broken pots Are evidence of ancient wrecks.

They find undisturbed amphorae

On every descent To the sea floor.

Khalil: During diving, we just came Across some shards of pottery

Inside the bay, And the further we look,

We discover more pottery, More ceramic,

And then we started discovering Single amphorae,

Intact amphorae.

Narrator: in emad's search for Evidence of wrecked ships,

The intact amphorae Are a puzzle.

Khalil: finding an amphora Or few amphoras

Does not definitely indicate An existence of a shipwreck

Because amphoras Could have fallen off a ship,

Thrown over a ship.

Narrator: to find shipwrecks And help explain

The height Of alexandria's lighthouse,

Emad must investigate further.

The team takes thousands Of high-resolution photos

To build a digital model Of the seabed.

The scan reveals A surprising clue --

The distinct forms of anchors From ancient ships.

Khalil: but finding an anchor -- Something else

Because anchors Do not fall off ships.

Narrator: The team discovers

A total of 14 anchors In the bay.

Khalil: finding more than one Anchor in the same place

Means that this had been Used frequently by ships.

Marsa bagoush is an ideal Example for a safe haven,

Or a safe natural anchor.

First of all, it's deep enough For ships to come in.

Secondly, the entire bay Is protected from both sides

By reefs,

So wherever the wind comes from, It's still protected.

Narrator: the discovery here, Not of the shipwrecks

But of a safe haven for ships,

Transforms emad's view Of the lighthouse

Up the coast at alexandria.

Khalil: To function as a lighthouse,

Which is to warn ships against Dangerous places for sailing,

It does not need to be 300 feet high at all.

Narrator: the lighthouse Does not need to warn ships

Of dangers along this coast.

Emad believes ancient ships On their way to alexandria

Can navigate safely Along egypt's coast without it,

And marsa bagoush is proof.

Half a mile behind The beach dunes,

Emad's team makes Another discovery

That reveals Why ships anchor here

On their voyage to alexandria.

Khalil: so, what we have here, Basically,

Is an exclusive network

Of underground wells And cisterns.

Narrator: This network of tunnels Is over 2,000 years old

And contains hundreds Of thousands of gallons

Of fresh water...

...A lifesaving resource For the ancient crews

Sailing along the northern shore Of the sahara desert.

Identifying certain spots Along the north coast of egypt

That contain fresh water Is an excellent advantage.

♪♪

Narrator: marsa bagoush is one Of the most important anchorages

On egypt's coast,

A stopping-off point on the Shipping lanes into alexandria.

Ancient sailors in these waters Do not need a mega lighthouse

In alexandria to guide them Along egypt's coast.

So is the purpose of The lighthouse to help ships

Navigate The treacherous approach

Into alexandria harbor itself?

Alexandria harbor was described As dangerous to get in

Because of the series of rocks

Surrounding the entrance Of the harbor.

If a ship captain was not Confident

Or was not sure Where to get in and out from,

They might end wrecking Even inside alexandria harbor.

Narrator: A tall lighthouse can warn ships Away from dangerous shorelines

And help them Avoid running aground,

But emad questions if a tall Lighthouse helps captains

To enter alexandria's harbor.

This lighthouse was an obvious Landmark that can be seen from,

You know, 50 kilometers out to the sea.

However, getting inside And outside of the harbor

In this case, lighthouse Would not be very useful at all.

In this case, You need more detail,

More specific reference points.

Narrator: Fortunately for ancient sailors,

The lighthouse isn't the only Tall landmark in alexandria.

The ancient egyptians carve Hundreds of granite blocks

Into monuments called obelisks.

Two of the most famous Are cleopatra's needles.

Today, these obelisks stand In london and new york.

They are already More than 1,400 years old

When alexandria's rulers Move them to their city.

They put up the needles Side by side

In the center of the harbor, Close to the shore --

A perfect landmark For approaching ships.

As long as sailors head straight For the obelisks,

Their ships are safe From the treacherous reefs

Lining the port.

A 300-foot-tall lighthouse Isn't needed to guide ships

Into alexandria,

So why is this structure So tall?

Emad has a surprising theory.

He believes It's not to warn people away

But to draw them into the city.

The lighthouse is A gigantic billboard

That announces alexandria To the world.

Khalil: It would be a banner, basically,

To draw the attention of ships And sailors coming into egypt.

They would head For this new town,

The new town with this big, Huge monument -- alexandria.

Narrator: The alexandrians build the Lighthouse so audaciously tall

To put their city on the map.

Nobody in ancient history Ever tried again

To build a 300-foot stone tower.

So what are The engineering secrets

That allow the lighthouse To stand so tall

And for so long?

[ stone crumbling ]

[ stone crumbling ]

Narrator: The lighthouse of alexandria Stands more than 300 feet tall.

New york's flatiron building,

One of the world's first Skyscrapers, is 20 feet shorter.

Abdelnaby: To build a stone building

That is almost Like a skyscraper,

There has to be some secret that Made it survive for that long.

Narrator: structural engineer Adel abdelnaby's day job

Is to make sure New bridges don't collapse.

But today, he investigates What type of stone

Alexandria's engineers Used to withstand

The extraordinary weight Of the lighthouse.

If you ask an engineer If he or she can build

A skyscraper from stone,

They would think You're crazy, you know?

We don't do that.

Narrator: stone is heavy, Expensive, and hard to work,

And the higher you build, The higher the risk

The building will collapse Under its own weight.

But working in the capital Of ancient egypt,

Alexandria's stone masons

Inherit a 2,500-year-old Tradition of building big.

And they have The building know-how

To pick just the right stone For the job.

Abdelnaby: We have egyptian pyramids.

They're built of limestone.

That's a structural material That's taken care of

All this mass and weight Of the pyramids.

You got -- the karnak temple Is mainly of sandstone.

Narrator: Limestone and sandstone,

The building blocks of egypt's Ancient mega structures,

Last for millennia In egypt's desert air.

Adel investigates If they are tough enough

To support a lighthouse Over 300 feet tall.

He uses the powerful vise In his lab.

So what this does -- It applies a compression force

Until it crushes the sandstone.

Narrator: The sandstone holds strong...

...Only to shatter At 57,000 pounds.

We're gonna do a crush test For the limestone.

And we're good to go.

Narrator: The limestone is stronger...

...But still shatters At 134,000 pounds.

It looks like neither limestone Nor sandstone is strong enough

To withstand the natural forces Acting on the lighthouse.

Abdelnaby: for a lighthouse, It's a slender building,

So it gets very high stresses.

That's why you needed A strong material

To support the building.

Narrator: with limestone And sandstone both ruled out,

Adel tests a third stone In the vise --

Pink granite.

This is the stone That egyptian masons used

To carve out huge obelisks.

The granite is still Going strong

When the vise maxes out at over A quarter-million pounds.

Abdelnaby: So you don't have a choice.

The best material to use Is granite.

That's the only type Of masonry blocks

That can survive These conditions.

Narrator: granite blocks are The perfect building material

To support the weight Of a 300-foot lighthouse.

But how do The lighthouse builders

Lock the thousands Of stone blocks together?

Adel thinks they carefully shape The stones for a perfect fit.

They chisel holes into Neighboring blocks

And connect them with dowels.

Metal clamps lock The blocks together,

And a special mortar of molten Lead fills any remaining gaps

To seal the walls Against the raging storms

And pounding waves Of alexandria harbor.

But out here, not all dangers Come from the sea.

Major earthquakes Regularly shake

The foundations Of alexandria's buildings.

Are the clamps connecting The lighthouse blocks

Strong enough to hold out Against these monstrous forces?

Adel doesn't think so.

Clamps are not enough to hold These granite blocks together,

Will not give you The resistance you need

For these strong Earthquake forces.

Narrator: so how does this Super-tall stone structure

Survive earthquakes For over 1,500 years?

[ stone crumbling ]

[ stone crumbling ]

Narrator: Alexandria stands in the center

Of an earthquake hot spot.

Archaeologists believe The legendary lighthouse

Survives 20 major tremors,

Each topping 8 On the richter scale...

...Before finally Falling into the sea

More than 1,500 years After its construction.

Even today, Earthquakes this powerful

Wreak total devastation.

The 2008 earthquake In the chinese sichuan province

Hits 8 on the richter scale.

It kills 87,000 people And leaves 5 million homeless.

So how does The lighthouse of alexandria

Survive such deadly tremors For over 1,500 years?

It could be because The city is home

To some of the most Brilliant minds in history.

Alexandria's rulers are hungry For knowledge and power.

They make copies of all Manuscripts entering the port

And put them into The great library of alexandria.

This vast collection becomes A beacon of intellect

That attracts scholars From across the ancient world.

It's here that philosopher Eratosthenes

First calculates the Circumference of the earth...

...And the celebrated Mathematician euclid

First records the fundamental Principles of geometry.

The builders of the lighthouse Live in a time

Of rapid scientific innovation,

And the engineering of their Stone goliath is no exception.

Structural engineer Adel abdelnaby

Is about to test An ingenious invention

He believes The ancient engineers used

To make their lighthouse Quake-proof...

...A mortar of molten lead

That they'd pour Between their building blocks.

Abdelnaby: We do a lot of tests.

Usually, most of our tests Are on modern building

Like steel and concrete, Reinforced-concrete building,

But today, we're doing The lighthouse test.

Narrator: adel uses An earthquake simulator

To investigate This special mortar.

He wants to find out How it changes

The properties Of the stone tower.

Abdelnaby: Oh, that's good.

When you have an earthquake,

You're pretty much shaking Your building back and forth,

So that generates huge forces,

So we're representing These forces

By using an actuator here.

Has to be too tight. We don't want any weak link.

The whole idea is that we're Simulating earthquake loads

Until we fail this wall.

We're gonna see how much load It's gonna take.

Narrator: Adel's hydraulic pumps

Rock the granite wall And its mortar

With a 10,000-pound force.

Abdelnaby: that's pretty much Like an 8.0 earthquake.

Narrator: the lead compresses As the wall shakes.

This give in the structure Allows the wall

And the lighthouse to roll With the punches during a quake.

Abdelnaby: Still not broken,

Even with a magnitude-8.0 Earthquake.

It's pushing the steel,

And we can't break it With this molten lead.

Narrator: Adel inspects the damage.

Abdelnaby: The wall is intact.

There is no even minor cracks.

Everybody would tell you That's a wall

That has never experienced An earthquake before.

That's a brand-new wall.

Narrator: Adel believes alexandria's Ingenious lead mortar

Protects the lighthouse walls

Against even the most powerful Earthquakes.

I have never seen this type of Behavior in any types of walls.

That's even stronger Than reinforced-concrete walls

That we have tested before In this lab.

Narrator: alexandria's Granite-and-lead lighthouse

Appears indestructible.

Adel's tests reveal How it can stand for so long,

Surviving 20 massive earthquakes And more than 1,500 years.

The ancient egyptians build The lighthouse

For the long haul.

They incorporate the smartest Alexandrian engineering

Into its structure.

Adel believes they even use The same tricks

That modern engineers use To build skyscrapers

That can ride out Monster quakes.

To build a skyscraper,

The ideal way to resist Earthquake loads

Is to have very strong walls At the outside of the building,

So that's exactly What the egyptians did,

And that's exactly what we do In modern days as engineers.

Now we realize that the Egyptians have figured this out

Before we did.

Narrator: The alexandrians know that a Building with rigid foundations

Is vulnerable in an earthquake.

♪♪

So they build their lighthouse

So it can move freely On its foundations

And ride out the tremors Of a quake without breaking,

So how does the lighthouse Finally fall?

Adel uses archaeological data To simulate the exact forces

He believes destroy The real lighthouse.

The yellow pixels reveal A structural achilles' heel

Where the building fails.

We got a lot of movement

At the middle segment Of the lighthouse,

And as you can see, there is A partial collapse of this part,

And that matches very well With the historical data

We have regarding the failure Of the lighthouse of alexandria.

Narrator: Adel's virtual model reveals

That it's the upper stories That fail...

...Where adel believes There's no lead mortar

To hold them together.

They didn't use lead at the top,

And that's why the collapse Of the lighthouse

And the failure mainly happened

At the top segments Of the lighthouse.

We saw that the base survived In every single earthquake.

Narrator: Engineering brilliance keeps The lighthouse of alexandria

Standing for so long.

Its height and strength make it A wonder of the ancient world,

But does an even greater Achievement

Represent its crowning glory --

An ingenious mirror system

That turns the beacon of Alexandria into a weapon of war?

[ stone crumbling ]

[ stone crumbling ]

Narrator: The lighthouse of alexandria is A marvel of ancient engineering,

Over 300 feet tall,

Standing for more than 1,500 years,

One of the seven wonders Of the ancient world.

Is its real wonder its ingenious And powerful beacon?

♪♪

At the base of the lighthouse -- An immense doorway.

It opens into a 240-foot shaft.

It makes it easy to winch up Fuel to a chamber at the top.

In here, a mighty fire burns Through the night.

Some scholars believe A system of mirrors

Focuses the light so much

That the lighthouse is visible 35 miles away.

♪♪

But can it produce, As rumors claim,

Enough heat To set a ship on fire?

Marty jopson builds Scientific models.

Today, at his workshop,

He investigates If the lighthouse lives up

To its fearsome reputation...

As a death ray.

Marty uses modern equipment

To replicate the power Of the ancient beacon.

Jopson: I've taken a space blanket,

Sucked the air out from behind,

And you get a perfect parabola,

Which focuses the light Into a point.

And the idea is, I'm then gonna focus that

Onto this beautiful [laughs] Model boat

When the sun comes out.

These are welding glasses Because the focal spot

Is so bright, It's quite dazzling.

Narrator: marty moves the target Into the death ray's kill zone

And angles the mirror To capture the sunlight.

I just need to bring this in A little bit more

To about there.

Let's see how that is.

Right. Let's try and set it On fire now.

Okay, sun's power on, And full sun,

And, whoa, immediately, It's burning!

That...

Narrator: the mirror focuses The sun's rays

To scorch The wooden ship's hull.

Yeah, it's burning! It's burning!

Hee-hee! We set fire to it.

Narrator: within seconds, The whole ship is ablaze.

All of the energy of the sun That's landing on this mirror

Is being concentrated to a point

About two centimeters In diameter,

And that is then Setting fire to it

Because the temperature there is In excess of 550 degrees.

That has set fire to that, I think.

Yep, that's set fire to that Quite effectively.

Narrator: Marty's built a miniaturized Ship-burning weapon.

Can the ancient greeks Do this on a larger scale?

Their biggest challenge -- To focus the light onto ships

Across a much greater distance.

Jopson: Archimedes was an ancient greek,

And he was A brilliant mathematician

And a brilliant inventor And all sorts of things,

And there was a legend That has it

That he built Something like this --

A burning mirror To set fire to the ships.

And we know that He studied in alexandria.

Narrator: how can the greeks Build a death ray

With the technology available In the 3rd century b.C.?

Archimedes is one of The most brilliant engineers

Of the ancient world,

Famous for designing Fireball catapults

And ship-grabbing claws.

At the library of alexandria,

He studies the principles Of optics and mirrors.

Some scholars believe Metalworkers at this time

Have the skill to craft Large high-precision mirrors.

It's technically possible The lighthouse engineers

Combine archimedes' knowledge Of optics

With superb craftsmanship

To create A lighthouse death ray.

Now, there are lots of ways You could do this.

The one of the ways that We believe archimedes did it

Is that he might have had Small hexagonal mirrors,

So sort of an array Of little mirrors,

Each that could be focused Separately.

You could've done it With polished shields.

You could've done it with just, Like, a big sheet of copper

Or brass that you polish And get it into the right shape.

There's all sorts of different Ways this could've been done.

Narrator: to be sure the Lighthouse can function at night

As well as in bright daylight, Marty has another test.

He's proved his device Is a killer at short range.

But is it also a lifesaver At long distance?

Normally, When sun hits the mirror,

It's focused to a focal point, Sort of about there, I reckon.

If we put some light here -- And it could be, say, a bonfire

At the top of the lighthouse Of alexandria, for example --

Then what you'll end up with Is a beam

That shoots across the valley, Or at least that's the theory.

The sun's about to set,

So we can give this a try And see how far we can see it.

Narrator: marty replicates The lighthouse bonfire

With a small l.E.D. Bulb.

Jopson: power on.

So, let's see Where I can see it from.

Narrator: as the sun drops Behind the horizon,

Marty dashes 300 feet To the end of the field.

Can he make out the bulb's light Reflected in the mirror?

Ah! That is [laughs] Ridiculously bright.

We're, what, 300 feet, Something like that,

And it is one light About, ooh, yea big

That's creating all that.

But the question is, How bright will it be

If we go right down In the valley?

♪♪

[ laughs ]

That is astonishing! I'm gobsmacked.

It is so bright!

I mean, I reckon we've come down About a mile away

Onto the main road, and it's -- I mean, you can see.

Sort of on the top of the hill, You can see the car headlights,

And it is 10, 20, 30 times Brighter than those,

And this is one l.E.D.

I mean, you could imagine that If they had this

At the top of the lighthouse,

That would've been Pretty astonishing.

Narrator: the lighthouse Of alexandria is a marvel

Of ancient engineering...

...A combination of thousands Of years of egyptian know-how

Into how to build big

And the technological genius Of the ancient greeks.

Jopson: alexandria was An extraordinary place.

It was a meeting place Of brilliant minds.

Narrator: from its Granite-and-lead construction...

...To its miraculous mirrors,

The architecture, scale, And sheer ambition

Of the legendary lighthouse Of alexandria

Combined to create a marvel Of engineering brilliance

And a true wonder Of the ancient world.

♪♪

♪♪

♪♪

♪♪