Unearthed

Angkor Wat, Cambodia.

The largest religious monument ever built.

The ancient Khmer civilization constructed

this magnificent Hindu temple 900 years ago...

When you get up close and you look at the detail,

it is truly an absolute masterpiece.

The crowning glory

of a once-great empire.

It's extraordinary on so many levels

that it's very difficult to even comprehend.

Why was this gargantuan temple built

seemingly in the middle of nowhere?

And how is it still standing after centuries of neglect,

ravaged by jungle trees and monsoon rains?

To unearth the truth, we'll explore

the temple's structure stone by stone.

We'll expose its hidden chambers and lost tunnels

to reveal the astonishing secrets

of the long-lost civilization

that built this ancient wonder.

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Angkor Wat, the largest temple on earth.

This massive structure dominates the jungle landscape

of northern Cambodia.

But for centuries, its sandstone towers

and carved walkways were lost to the forest,

hidden beneath an impenetrable canopy of trees.

Now archeologists investigating Angkor Wat are revealing

its hidden secrets.

Workers have cleared the trees to reveal

a temple complex covering over 500 acres,

and there could be more.

Archaeology teams use innovative laser technology to hunt

for the long-lost city they believe

must once have surrounded Angkor Wat.

Other experts search for clues inside the temple

to solve the mysteries of how and why it was built.

It's perfection in terms of carving.

It's perfection in terms of dimensions,

in terms of rhythm of spaces within the temple.

This required an extraordinary vision.

Ancient architects designed Angkor Wat to inspire

awe and wonder.

A majestic staircase led pilgrims

to a magnificent central atrium

where they came face-to-face with Vishnu,

a supreme being in the Hindu faith.

Five imposing stone towers Rose above their heads,

symbolizing the sacred mount Meru,

home of the gods.

Built using half a million tons of stone,

Angkor Wat is a spectacular

re-creation of heaven on earth.

But why did the ancient Cambodians build this temple

so much bigger than any other?

Simon Warrack has spent decades investigating Angkor Wat

and its surrounding temples.

He believes the answer to this mystery lies in decoding

the intricate carvings

that adorn the temple walls.

We're in the third enclosure of the temple of Angkor Wat,

and in this enclosure, we have more than half a mile

of carved bas-reliefs.

The carvings tell the story

of the ancient civilization who built the temple...

The Khmer.

They depict the army's military victories,

and they give us an image of a great ruler...

King Suryavarman ii.

So here we are in front of king Suryavarman ii himself.

This is the first portrait of a Khmer king

in the history of Khmer art.

Here he is sitting on his throne looking very regal,

surrounded by his counselors

and his ministers, several holy men.

And wonderful umbrellas to shield him from the sun,

fans, fly whisks.

All the accoutrements of royalty are here.

Critically, king Suryavarman wasn't born to rule.

He had seized power from his great uncle,

and Simon is convinced that

Angkor Wat's huge size was a grand political statement

to win over his new subjects.

Carved here is the message that the king wanted

to get to his people.

In a way, this is the campaign ad for Suryavarman ii.

Suryavarman didn't just want to be seen

as a rightful king.

He wanted to be revered as a god.

So he built a temple with an extraordinary secret

that links it to the heavens.

Each year at the spring equinox,

the sun rises directly over the central tower.

A hole in the capstone focuses

the sunlight down into the temple.

It shines through a hole in the floor below

and down a 90-foot shaft

to a secret chamber deep underground.

Some experts believe that Suryavarman

designed this secret vault to hold his mortal remains.

If they're right, Angkor Wat is not just a temple.

It's a spiritual machine to elevate the god king

to his rightful heavenly throne.

But this idea creates another big mystery.

If Angkor Wat was designed to be Suryavarman's tomb,

it had to be constructed

and decorated in time for his death.

The reign of king Suryavarman ii was 32 years.

That's a very short time to build the biggest

stone religious building in the world.

The great European cathedrals built in the same era

took centuries to complete.

Yet they're a fraction of the size of Angkor Wat.

So how did the Khmer engineers build this remarkable triumph

in such a short time?

Simon thinks that the solution

could be a vast supply of manpower.

To test his theory, he visits another Khmer temple...

Phnom Bakheng...

Where a team of stonemasons

are rebuilding the temple's southwestern wall.

Simon experiments by chiseling a sandstone block.

He wants to investigate how long it would have taken the Khmer

to do the same job 900 years ago.

Roughing out with a point chisel and a big hammer

is really hard work.

And that would have been done by the less-skilled teams.

To make sure the blocks sat flush against each other,

they had to chisel and then sand them

until they were perfectly smooth.

The most uncomfortable thing about doing this kind of work

is, of course, the heat and the dust.

Simon's an expert stonemason,

but it still takes him over two hours

to prepare the block for the temple wall.

This here is a relatively small block.

This is one you can actually move by hand.

The blocks in Angkor are up to 10 tons

and were placed in situ and then worked by hand.

The size of that task is very difficult

even to actually imagine.

Simon suspects

it would have taken a Khmer stonemason up

to eight hours to prepare each of the massive blocks

used to build Angkor Wat.

And with 5 million blocks to prepare,

Suryavarman would have needed thousands of stonemasons

working every day

to complete the temple within his lifetime.

And this would have been just a fraction of the workforce.

Suryavarman also needed the materials to be quarried

and transported to the jungle site.

You can estimate by doing a simple calculation

that there was between 200

and 300 blocks per day arriving on site.

And that is almost impossible to conceive.

Angkor Wat sits in the middle of the jungle.

The nearest sandstone is in the Kulen hills

25 miles to the east.

Archaeological research has revealed that the Khmer

cut canals to join up the rivers

to create a transport route direct

to the building site.

They crafted bamboo rafts to support the sandstone blocks.

And the current effortlessly carried them towards Angkor Wat.

This system provided a constant supply of sandstone

to an army of builders

who worked tirelessly to erect a temple.

We can imagine an almost solid stream of stone going

from the quarry to the site

at the height of the building period...

A site I would love to have been able to see.

To build a temple of such epic proportions in so few years

would have taken hundreds of thousands of workers,

perhaps the largest construction task force

ever assembled in the pre-industrial world.

The size of the team must have been extraordinary

and really vast.

It shows a capacity for organization,

which is characteristic of a very,

very great civilization.

Through sheer force of numbers,

king Suryavarman achieved his extraordinary vision,

and the final stone of Angkor Wat was in place

before he died.

But this surprising fact presents another mystery.

If such a vast workforce was needed to construct the temple,

where did they all live?

Today the temple appears to sit like an island

in a sea of dense jungle.

Is new technology about to reveal

Angkor Wat's most closely guarded secret?

Today tourists marvel at the splendor of Angkor Wat

and its vast moat.

Designed to glorify the rule of an ambitious king,

it contains hundreds of grand columns,

and its walls and towers are adorned

with thousands of exquisite carvings.

But 900 years ago, it would have looked even more magnificent.

Its roofs were beautifully gilded.