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 awe 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]

Since the planet's very first buildings were created,

pioneering engineers and architects

have been united by a single driving force, religion.

Divine inspiration has led

to groundbreaking construction techniques,

pushing the limits of engineering.

Great temples built to honor the gods

and it continues to this day.

- Religion is still an incredibly important part

of the modern world.

- [Greg] Many are minimalist in design

like India's Lotus Temple constructed in under 10 years.

Sheathed in pure white marble,

27 blooming petals cover the structure.

But in the ancient world,

temples were often far more elaborate

built over decades or even centuries.

- Nothing really compares with the grandeur

and the splendor of the ancient temples.

- It's a building that all

the ancient cultures have in common.

- [Greg] No expense was spared

as engineers sought to create ever greater wonders.

- Primitive tools and technology were not enough

to hold back their ambition.

- [Greg] They achieved breathtaking buildings,

each with its own story to tell.

But one stands out from the rest,

hidden deep in the Cambodian jungle,

a temple to eclipse all others,

Angkor Wat.

A 900 year old complex

rising from the flood plain of the Mekong River.

- It is one of the largest

religious structures in the world.

- [Greg] A vast monument covering more than 400 acres.

- You can't really fail to be impressed by Angkor Wat.

And when you walk through the corridors,

it's an incredible experience.

- [Greg] Stone shrines ascend one upon the other,

as if reaching for the heavens, endless hallways carved

with some of the longest reliefs in the world,

and at its center a magnificent structure

as tall as the Sydney Opera House.

- It's a home fit for the gods.

- [Greg] But Angkor Wat is about more than sheer scale.

It's also a masterpiece of craftsmanship,

sculptural decoration, and of course, engineering.

The temple is accurately oriented to the setting sun

and 18 further astronomical alignments

appear to be built into its fabric.

This precision stone masonry not only honoring the gods,

but also imperative for the temple stability.

Constructed in a monsoon plagued swamp land.

- This would have been an astonishing challenge

to get this thing built in a way that just didn't sink in.

- [Greg] It was completed in just 30 years.

In comparison, some of the great medieval cathedrals

took over a century to build.

Angkor Wat was constructed on a completely different scale

and still stands many centuries later.

- Even today, it's an incredible building.

- [Greg] Many claim the power of the gods

must have inspired such engineering genius

to produce the peak of temple construction.

And Angkor Wat is still shrouded in mystery.

How did an early society with little technology

build these colossal structures?

- Today, we have modern building tools and techniques

that really help engineers and designers

push the boundaries of creativity

when designing and building places of worship,

but really nothing compares to those ancient buildings.

- [Greg] And what exactly

was this ancient wonder designed to do?

- We have many ideas,

but we're always making best guesses on the basis

of what archeological evidence there is to date.

- [Greg] Was it purely a house of worship

or did it serve another more mysterious function?

To fully understand its secrets and engineering,

we need to look further back

to what could be the very first temple.

A divine design built by a civilization

thought to have no metal tools,

no formal society, or even a written language.

How could such a primitive culture

build a monumental temple to the gods?

In 1963, a survey of Southeastern Turkey

revealed broken slabs of limestone scattered on a hill.

Initially, they were assumed to be the remains

of an abandoned medieval cemetery.

But 30 years later, German archeologist Klaus Schmidt

decided to investigate

the stone littered hilltop for himself.

- He immediately tweaked what he was looking at

and he realized that this was an earlier site

and this had to be highly significant.

- [Greg] Buried beneath the surface,

Schmidt unearths something extraordinary, Gobekli Tepe,

gigantic carved stones, crafted and arranged in circles.

Radiocarbon dating produced astonishing results.

The site was around 11,000 years old,

built just after the end of the last ice age.

- It coincides with the dates we have

for the very beginning of farming

- [Greg] More than 5,000 years

before the invention of the wheel,

somehow these elusive peoples overcame

immense engineering challenges

to produce giant stone monuments in a sprawling complex,

including T-shaped monoliths

ranging from 7 to 18 feet in height.

- This is a massive undertaking

to put together these kinds of shrines.

The size of these stones is extraordinary,

higher than our head height.

- They have to be chopped out of the limestone bedrock.

They have to be prized out and then they have to be dragged

to the place of construction.

And there, they have to be carefully carved.

- [Greg] An operation that would have required

hundreds of people

with only simple stone aged tools at their disposal.

- We're looking at quite a remarkable

engineering feat to do this.

- [Greg] So was this mysterious place a home

or an ancient holy site?

Clues may lie on the stones themselves.

- Many of these stones are carved in intricate detail

including mammal-like creatures,

bird-like creatures, lizard type creatures.

- And in the center, there's two large T-shaped stones.

We also see that they have human forms

and we can see their hands and their arms represented.

- [Greg] These carvings may depict the bodies

of stylized people or their mysterious deities.

It's led some experts to believe

this must have been a place of worship.

- Archeologists have argued that Gobekli

is some kind of ritual site.

It's highly unlikely that this was a permanent settlement.

- [Greg] It seems early prehistoric communities

thought the best way to keep the gods happy

was to build and decorate monuments in their honor,

but surely lifting these stones

required some kind of engineering technology?

Even today, it would present a challenge,

but it would have been infinitely harder

before the invention of the wheel

and another engineering breakthrough, the pulley.

A mechanism designed to make it easier to move heavy loads,

a pulley can have the force needed in lifting,

effectively doubling the weight a single person can lift.

Add multiple pullies, and the figure keeps on rising.

Onboard a 17th century ship,

a single deck hand could use a pulley system

to haul up a sail weighing several times his own weight.

And in the industrial era,

machines developed ever greater lifting power.

Combined with engines and hydraulics,

the biggest cranes still use the physics of the pulley

to move insanely heavy objects.

- Cranes are an incredibly important tool

in modern construction.

There are very few structures that I can think of

that wouldn't require a crane for some reason.

- Crane technology has got more and more powerful,

so we can lift higher, faster,

heavier weights than ever before.

- [Greg] Standing 820 feet tall,

Big Carl is the world's largest land-based crane

powered by 12 engines

and capable of lifting up to 5,000 tons.

But in the millennia before the invention

of these technologies,

how did the ancients move monumental stone loads?

It's an engineering conundrum

that's puzzled experts for centuries.

Nowhere more so than at one prehistoric site

in Southern England, Stonehenge.

- Stonehenge is one of those absolutely

iconic archeological sites.

- [Greg] Dating back more than 5,000 years,

the monument is a circular arrangement

of massive sarsen stones, each way around 25 tons.

Most archeologists now agree the stones were both carried

via water networks and hauled over land

before being raised into position

using plant fiber ropes and timber platforms.

Given the huge efforts involved,

was Stonehenge an important ancient temple?

In the 18th century, a discovery suggested

that the standing stones hadn't been placed at random.

Instead, they seem to be precisely laid out

for one specific function.

- All the stones of Stonehenge were built

around an axis of symmetry

and that axis was on the solstice line

pointing out to the Northeast to midsummer sunrise

- [Greg] Stonehenge was designed to mark the longest day,

when the sun rises directly over the Heel Stone

and casts a long shadow that enters the circle

through the main entrance.

Not only did an ancient civilization

raise and carve these giant stones,

but they aligned them perfectly with astronomical events,

a real feat of precision engineering.

By observing the sun's movements

and coordinating hundreds of well-organized people,

ancient engineers created a masterpiece still admired today.

- There is something very special

about Stonehenge as a place

because of its special solar alignment.

- [Greg] It leaves little doubt

that those who built Stonehenge were as interested

in the sky above as in the land below.

So was this ancient monument

some form of prehistoric solar observatory?

Humanity's fascination with the sky above

hasn't diminished across the millennia.

Today, one of the largest and best developed observatories

in the world is located on the summit of Mauna Kea, Hawaii.

Constructed over 13,000 feet above sea level

in a place with little light pollution, engineers have built

more than a dozen world-class telescopes here.

Most powerful is the twin Keck observatory.

Each telescope stands eight stories tall, weighs 300 tons,

and operates with nanometer level precision.

Equipped with two 33 foot wide mirrors,

the twin telescopes have produced incredible results.

Images of distant objects from across our galaxy and beyond.

Another of the great ancient civilizations

seems to have shared this obsession

with the heavens, Ancient Egypt.

From 3,500 BC, Egyptian engineers built

some of the greatest temples in world history.

- Egypt was known anciently

as the most religious land of all.

- [Greg] Their monuments emphasized order,

symmetry and grandeur,

and were seen as houses for the gods or kings

to whom they were dedicated.

- The ancient Egyptians were prolific temple builders

because the gods were very critical to their society.

- [Greg] But what drove the ancient Egyptians

to build temples on such a monumental scale?

One of the greatest was erected in 13th century BC

by the Pharaoh Ramses the Great,

the twin temple of Abu Simbel.

- The template is a huge structure

with everything cut into the rock

rather than built on a flat surface outside.

- [Greg] Carved directly out of the mountain side

dedicated to multiple ancient Egyptian gods,

it also functioned as a lasting monument

to the king and his queen, Nefertari.

Four seated colossi of Ramses the second

guard the 98 foot high Grand Temple entrance

- The whole pylon gateway and the statues themselves

are all carved as one with the living rock.

- [Greg] With only simple tools,

the ancient Egyptians bore over 200 feet

to Abu Simbel's inner chamber.

And this temple too is precision aligned.

On key dates, daylight penetrates

deep into the temple interior.

Once on the 22nd of February,

celebrating the agriculture and cultivation season.

And again, on the 22nd of October,

marking the onset of the flooding season.

The statue of Ramses the second

and a moon are brilliantly illuminated.

- Where you have a dark space

that is just suddenly lit up at certain times,

it's hard to express how impressive

that would be if you were there.

- [Greg] While the statue of Ptah,

god of the Egyptian underworld,

remains in perpetual darkness.

- This temple is a true example of ancient Egyptian genius.

- [Greg] Abu Simbel survived through ancient times,

only to be threatened by the modern world.

Following the decision to build a dam at Aswan

in the early 1960s, it was revealed

that the temple would be flooded by the rising Nile.

But engineers came up with a remarkable plan

to ensure its survival,

move the entire 16,000 ton structure.

- UNESCO launched an operation to rescue the temple,

so it was cut into small pieces.

- [Greg] Ramses temple was sliced

into more than a thousand blocks,

each weighing between 3 and 20 tons.

They were moved to a desert plateau 210 feet higher

than the original site, well above the new water line.

It took more than two years of painstaking work,

but eventually the blocks were all pieced back together.

- It was so interesting to see the way

in which they deconstructed and reconstructed

this monumental building from Ancient Egypt.

- [Greg] A vast engineering jigsaw puzzle.

In 1968, Abu Simbel reopened in its new higher location.

This remains one of the greatest feats

in the history of archeology,

an iconic Egyptian temple rescued

thanks to epic engineering.

But Abu Simbel was far from the largest temple

constructed in Ancient Egypt.

- The great temples were built to impress mainly

to make a point about who you were on Earth

- [Greg] Exhibiting features

that demanded formidable engineering

combined with great artistic flair,

towering obelisks, immense gateways, and vast halls.

Achievements never seen before in the ancient world

and one out shown all others, Karnak.

Sitting on the East bank of the Nile in Luxor,

it's the largest religious complex ever constructed

in the ancient kingdom.

- Structure's going off

for hundreds of meters in every direction.

- It's mind boggling array of temples,

shrines, sacred roots, it's enormous.

It's the most stunning temple on Earth in many ways.

- [Greg] Covering an area of more than 250 acres,

Karnak is bigger than some ancient cities.

At the heart of the complex is the Hypostyle hall.

Today, it's drenched in sunlight,

but originally the hall was designed

to protect the gods from the beating midday sun.

- The Hypostyle hall would have been completely covered,

so it'd be quite dark.

- [Greg] The royal builders faced an immense problem.

Enormous beams were needed to span the vast distances

between columns, resting on these would be a huge roof.

- The main challenges with a single span roof

are stability and strength.

You've gotta take into account the material

that you're building it out of

and it's gotta be able to support its own weight.

- [Greg] Egyptian engineers needed something stronger

than the limestone blocks used to construct the pyramids.

- Sandstone was easily available

from the quarries to the South

and also had better qualities for support than limestone.

- [Greg] A tough material, perfect for the Hypostyle hall.

The first step was to erect

the towering sandstone columns 49 feet high.

- There are a few theories

as to how these columns are put together.

I mean, clearly they quarried in blocks in separate drums

'cause you can see the various components of them.

- [Greg] Each piece weighs over four tons,

too heavy to be lifted by laborers.

So ancient engineers must have invented

an ingenious new method.

- How you actually construct these,

you need some kind of scaffolding and it seems

the Egyptians might have used natural scaffolding.

- [Greg] The theory is that every time

a layer of stone drums was added,

the space around was filled with a layer of sand

to create a new working platform.

- Working all the way til you've got at the top

and then you then start removing that sand.

- [Greg] It left behind a forest of 134 perfect columns,

most as tall as a seven story building.

And with roof beams in place,

Egyptian engineers had created the largest enclosed room

of any religious building in the world,

covering an incredible 50,000 square feet.

A structure and setting worthy of the gods,

the Hypostyle hall was the greatest feat

of roof engineering in the ancient world.

In recent times, engineers have constructed the world's

most complex roof for a very different purpose.

In the Ukraine in 1986,

one of Chernobyl's reactors exploded.

The world's worst nuclear disaster.

The blast blew off part of the power plant's roof

sending plumes of radioactive material into the air.

To stop it leaking deadly radiation,

engineers needed to get a new roof in place

and seal up the whole structure.

But after just five minutes exposure to the radiation,

a worker might have only a few days to live.

How could it be done?

Teams worked in relays to try and lock in

the radioactive materials,

assembling a massive covering of concrete and steel,

but these repairs were made in haste.

10 years later, radiation levels had risen again

and the whole structure was in danger of collapse.

It called for a colossal engineering solution.

Scientists came up with the idea

of constructing a giant steel arch called

the New Safe Confinement weighing over 35,000 tons.

It was the largest movable

land-based structure ever attempted,

but this Goliath had to be engineered to perfection.

Its frame, a huge lattice construction

of tubular steel units

supported by two longitudinal concrete beams,

strong enough to withstand tornadoes,

earthquakes, and extreme temperatures.

- The Chernobyl containment system is astonishing really,

the cover itself has to deal with

some really extraordinary circumstances

to do with radiation

and so the materials they use are specially chosen.

- [Greg] The structure also protects

against damage from within.

- In the arch, you've got the tubular steel construction

that's coated in polycarbonate panels

to protect against that radiation damage.

- [Greg] In November 2016, six years after work began,

the New Safe Confinement was rolled into position.

Thankfully it worked.

At 843 feet long and 357 feet high,

it completely seals in Chernobyl's toxic radioactive ruins.

A giant protective shield built to last

for the next 100 years.

Ancient engineers also designed their structures to last.

Nowhere more so than in a civilization emerging

in the seventh century BC

along the Northern coast of the Mediterranean Sea,

Ancient Greece.

- The Greeks took temples to a whole new level

building these huge structures.

- The Greek temple form is one was shared

across the Mediterranean.

And it clearly is symbolically significant,

as well as being architecturally very impressive.

- [Greg] The Greeks embraced Egyptian ideas

of size and impact in their own temples,

incorporating columns,

as well as posts and lintels in their designs.

But while the Egyptians built their temples

for a select few to see from the inside,

Greek temples were constructed

to be admired by everyone from the outside.

- Greek temples are made for the exterior view.

They are made for us to look at

from the outside, not from the inside.

So light would have been fundamental in every way

to how they're built and why they were built.

- [Greg] This change called

for a new approach to engineering.

The Greeks believed that the secret

to making a great building lay in mathematics.

They sought refinement and perfection,

carefully designing and measuring their temples,

making sure all angles, shapes and sizes were exact.

Greek engineers work to set proportions,

sticking to strict column height to diameter ratios.

Stones were carved with utmost accuracy

and tightly locked together, enhancing the beauty

and structural stability of their designs.

Their meticulous mathematics enabled engineering advances

and the construction of temples unlike any that came before.

- The Greek temples were very distinctive,

you couldn't miss them if you saw them.

- [Greg] Their greatest accomplishment still stands today,

the Parthenon.

- It is really the apogee, it's the height

of temple construction in the classical period.

- [Greg] Sitting high atop a rocky outcrop

above the city of Athens.

- The intricate detail, the quality of the carvings,

and the sheer scale of this extraordinary temple.

- [Greg] Unprecedented in both quality and quantity

of architectural sculpture.

- It's a statement of perfection, it's a statement of power,

and it's a statement of huge wealth.

- [Greg] The Parthenon was dedicated to the goddess Athena,

patron of the city of Athens.

- The Parthenon really is

the pinnacle of Greek construction.

It celebrates everything the Greeks believed in.

- [Greg] But such a gargantuan building project

would demand engineering excellence.

The first challenge was to acquire

a material worthy of a goddess.

- What was used to build the Parthenon

was the finest marble in Greece

and this is very carefully selected.

- [Greg] This would be the largest building in the world

to be built entirely of marble,

calling for an estimated 13,400 blocks

weighing roughly 30,000 tons.

- It required a lot of labor.

It was a massive project that really required

a tremendous wealth for the city of Athens.

- [Greg] Historians estimate the Parthenon cost the city

as much as 800 silver talents, a vast sum

equivalent to around $16 million in the 21st century.

To the Athenians, it seemed justified at any price,

an icon of perfection,

but this marvel isn't as neatly symmetrical as it seems.

Its structure contains an engineering secret.

- Well, one of the things that is baffling

about the Parthenon is the fact

that it's got all these imperfections.

- [Greg] Subtle curves make each piece of the temple unique

varying by fractions of an inch.

These tiny discrepancies were no mistake

on the part of Greek engineers.

- If you had all sorts of straight lines there,

it would look a little bit off.

The columns would look a little chubby.

The base would look like it sags in the middle.

- [Greg] To create the appearance of perfection,

the ancient Greeks came up

with engineering to trick the eye.

They incorporated these almost imperceptible adjustments

throughout the temple,

creating the illusion of straight lines.

Each of the 46 columns has a gently curving profile

and leans inward.

Engineers even raised the temple floor slightly

in the center, from a distance,

giving the impression of a completely flat surface.

- When you look at the building,

it actually takes out some of the optical effects

of having curved eyeballs and perspective

to give an impression of an even

straighter building then is real, which I found amazing.

- [Greg] The Parthenon's perfection

is a brilliant engineering illusion

and these intricate refinements

required exceptional precision.

A level of accuracy challenging to achieve

even in the modern era.

Modern engineers still rely on mathematical principles

first laid down by the Greeks,

as they attempt their own optical illusions

in buildings across the globe.

Opened in 2016, the MahaNakhon Tower was recognized

as the tallest building in Thailand,

but its unusual appearance drew attention.

- Sometimes you look at it and wonder

should that be standing up?

- A pixilated ribbon swirls around the exterior,

peeling back at surface to expose an inner layer.

- Even as an engineer, when you look at it

it looks like it could fall down at any moment.

It's just a masterpiece of design.

- [Greg] However, this design created a huge challenge

for engineers to provide stability

able to resist lateral loads from wind or earthquakes.

The tower is built around a central wall

of reinforced concrete,

12 mega columns surround the core along its height,

supporting unbalanced gravity loads created

by the layout of the higher floors.

This ingenious engineering

made the structure's unique form possible.

A modern variation

on the Parthenon's ultimate optical illusion.

Greek mathematics had taken ancient engineering

to a new level,

but one ancient civilization would surpass even them,

the Romans.

Developing radical new forms for their temples,

incorporating bold ideas never previously seen.

- Architecture in the Roman times

was like nothing that had come before.

- [Greg] But Rome needed

entirely new construction techniques

and the engineering breakthroughs

that would make them possible.

- The Romans adopted a number of new engineering techniques

that were different from other cultures

around the Mediterranean

and it made the interiors as impressive as the exterior.

- [Greg] They created huge open rooms,

not only to house vast statues,

but also to store temple equipment and offerings.

- The Greeks, for example, were creating a large hall,

you would see a lot more columns peppering the space

compared to the Roman equivalent.

- [Greg] Roman engineers developed new forms

for their temples, constructing a multitude

of different structures across the empire.

But one marvel was the most visionary of them all,

the Pantheon.

Even today, almost 2000 years after its construction,

it remains one of the world's most breathtaking structures.

- It's an amazing survivor of the ancient world.

- [Greg] Believed to be a temple dedicated to all Roman gods

with engineering features more ambitious

than seen in any building before.

- In my mind, the Pantheon is

the most extraordinary building in the ancient world.

It reaches the height of architectural brilliant.

- [Greg] The Pantheon's claim to fame

stems from its mighty dome,

entirely unsupported unlike anything Rome had seen before.

- It is still an engineering wonder.

The dome is still the single largest

non-reinforced concrete dome in the world.

It's never been surpassed.

- [Greg] Covering a span of 142 feet,

it was twice the size of any dome yet built.

- The size of the dome is extraordinary

and the fact that they could build it

in a way that meant it did not need reinforcement

is quite a feat of engineering.

- [Greg] A landmark achievement,

but constructing this architectural wonder

would prove to be one of the greatest challenges

Rome's engineers ever faced.

- When you're building a dome,

you have to think about how to make it light

and reduce the pressure on itself

and how you're going to construct it

without it collapsing under itself.

- [Greg] How could such forces be controlled?

- The dome of the Pantheon was a real challenge

to construct, but using a number of innovative techniques,

they were able to create this huge structure.

- [Greg] Firstly, in anticipation of the weight of the dome,

engineers built within gigantic buttress-like walls

nowhere less than 20 feet thick.

They also reduced the weight of the dome itself

by punching out large square panels called coffers.

- The Romans also ensured that they kept the strength

of the dome with thicker sections at the bottom,

but then gradually getting thinner towards the top

to reduce the weight and the pressure on the dome.

- [Greg] And at the summit, a finishing touch, the Oculus.

A 27 foot wide skylight opening directly to the heavens.

- The Oculus also helped to reduce the weight

because it just simply took the material away.

- [Greg] It allowed daylight to pour into the interior,

illuminating its beauty,

but the final secret to this engineering feat

lies in a material only recently invented, concrete.

One of the greatest Roman engineering advances.

- It was liquid rock and that meant they could shape it

into the most extraordinary creations.

- [Greg] Today, concrete is the most widely used

man-made material in the world

and continues to create a whole new set

of building opportunities.

What begins as a bold idea in the mind of an architect

can be realized thanks to the versatility

and strength of concrete.

The Auditorio de Tenerife in the Canary islands

cuts a striking figure against the Atlantic Ocean.

Famous for its white concrete arc,

the first in the history of engineering.

The slender form of the 328 foot cantilevered wing roof

demanded a material lighter than stone,

but stronger than timber.

By constructing a steel skeleton

and reinforced concrete shell,

the concert hall's ambitious design was brought to life.

- You have this giant floating shell,

which looks like it's defying gravity,

and its construction was only made possible

because of concrete.

- [Greg] A material often considered ugly or dull

has proven fantastically useful in reshaping the world.

Ancient Rome didn't have the last word

in temple engineering.

Many Buddhist and Hindu temples found across Asia

boast some of the most intricate and elaborate designs

ever achieved in the ancient world.

- Temple building in Asia has produced

some remarkable structures over the last 2000 or so years.

- They have a lot of details

and they often create a very intricate carving.

- [Greg] Complex and impressive structures

made possible thanks to engineering ingenuity.

But one incredible structure hidden for centuries

in the Cambodian wilderness

rewrote the history of temples forever.

In 1860, French naturalist Henri Mouhot

was exploring the tributaries of the Mekong River

in search of exotic insects

when he stumbled upon something extraordinary.

A vast complex of 900 year old stone temples

long since abandoned.

Who was responsible for these highly advanced structures

and why build grand monuments in such a remote spot?

Answers seemed to lie with a mysterious ancient king.

Back in the ninth century,

an ancient civilization rained over the area

that would today include Cambodia

and parts of Laos, Thailand, and Vietnam,

the Khmer empire.

- Over a thousand years ago, the Khmer empire

was one the most powerful forces in Southeast Asia.

In 1113 AD, a usurper king of the Khmer named Suryavarman

seized the throne after murdering his uncle.

To avoid being overthrown by his enemies,

he had to establish himself as a god-king

in the eyes of his people.

So Suryavarman began the construction

of a majestic stone temple.

It would be dedicated to Vishnu,

but would also help him guarantee

his own place on the throne, Angkor Wat.

- Suryavarman built Angkor Wat

as a way of cementing his position,

demonstrating his rights.

- [Greg] The construction of great temples was a common way

for the Khmer kings to display their power.

- The Khmer built well over a thousands temples in the area.

- [Greg] But Suryavarman wanted his masterpiece

to surpass all others.

His plan was mind boggling in scale.

Angkor Wat would reproduce on Earth the world of the gods,

specifically the mythical mountain known as Mount Meru,

home of the Khmer deities.

The five peaks of Mount Meru would be represented

by the five spires of the temple.

- And beyond that, the moat represents the cosmic ocean

around that as well.

You see here, the kind of representation

of the cosmic landscape.

- [Greg] Angkor Wat would be a heavenly complex

carved in stone found on Earth,

but Suryavarman's workers had less

than a single lifetime to build it.

How would such an engineering feat be possible?

The first task was to clear the site

amid the steamy rainforest.

- It would have been incredibly challenging

to construct Angkor Wat's because not only was it

in the middle of the jungle,

but it was located in a flood plain.

- [Greg] Why did Suryavarman choose such a location

for his temple complex, seemingly in the middle of nowhere?

Archeologists began to unlock its secrets in 2007

thanks to space age engineering.

Satellites and aerial photographs were used

to analyze 1,100 square miles of the Cambodian landscape.

Ground sensing radar detected subtle differences

in surface moisture and plant growth.

A sign of architectural remains hidden below the ground.

With this cutting edge technology,

the team produced a detailed map

of the entire area surrounding Angkor Wat.

What they discovered was incredible.

The map revealed a gigantic ancient settlement

sprawling over a vast area.

- So we're not only talking about a very large temple,

but also a massive city.

- [Greg] The lost city of Angkor.

- [Mark] We didn't know how large Angkor was

for a long time, but it was revealing

that it's actually much more extensive than we thought.

- Angkor was one the largest

pre-industrial cities in the world.

- [Greg] Covering 385 square miles,

an area the size of New York City's five boroughs.

For six centuries, the city had thrived under the Khmer.

Comprising thousands of houses,

roads, manmade ponds, and canals,

the mighty capitol of the largest empire of its time

home up to a million people

with Suryavarman's magnificent temple at its heart.

But one thing continued to puzzle the archeologists,

how did the Khmer construct a stable city here

in heavily waterlogged soil?

Nightmarish conditions

for engineers seeking to build in stone.

- There are also challenges obstructing near water.

One of them is that the ground

tends to be quite variable and quite wet,

which isn't really great for big, heavy structures.

- [Greg] As if that wasn't enough, the yearly monsoon rains

could be expected to wreak further havoc.

Thankfully, the Khmer had built more than stone structures.

The 2007 survey also revealed

hundreds of interconnected canals, dikes, and reservoirs

operated over 460 square miles.

- The Khmer were masters of engineering water.

- [Greg] Khmer engineers dug channels up to 12 miles long

and more than 160 feet wide

and reservoirs covering thousands of acres.

A complex water management network used to store

and distribute water throughout the area.

- Because of the water management structure,

there was a greater retention of the water

that might otherwise have made the place quite waterlogged.

- [Greg] Through the 12th century,

Suryavarman's grand temple began to take shape.

Building materials were consumed on an unparalleled scale,

an estimated five to 10 million

precision cut sandstone blocks,

more stone than used to build the Great Pyramid of Giza.

Khmer engineers achieved a close fit

with a technique called abrasion.

- Blocks were cut to shape

and then ground against each other to achieve a better fit,

but also to generate strong friction between the blocks.

- [Greg] The temple then slotted together seamlessly

without the use of mortar or cement.

Based on knowledge of how shapes interlocked

and exploiting the natural weight

and friction between stones,

Khmer engineers produced the soaring details

that make Angkor Wat famous.

Spread across more than 400 acres,

the largest religious monument in the world by land area,

a stunning monument to Cambodia's golden age.

Across the ancient world,

temples showcase some of the most spectacular engineering

in all of human history.

But in the modern world,

other buildings are coming to rival them.

Where icons of a very different kind are honored.

- I think there are some similarities

between religion and sport.

And I say that speaking as an engineer

because the structures that you create

for both of them tend to be quite iconic, quite distinctive,

you know, make a statement about that city or that region.

- [Greg] Just like temples,

stadiums are places where people gather in huge numbers,

instead of honoring the divine,

they're honoring humans, or some might say super humans.

- People get together today in big modern stadium here

and worship their particularly team,

they do it in massive communities in astonishing buildings.

- [Greg] Built with the latest techniques and technology

to create spectacular spaces, massive retractable roofs,

movable seating, and superstructures engineered

to withstand earthquakes rated 8.0 on the Richter scale.

- When designing these stadiums

how are you gonna make it worthy of the fans passion

and energy that they bring into this space?

Making sure that it has unique features

that I think is really important

in terms of actually meeting the needs

and the aspirations of these fans.

- [Greg] These are some of the biggest,

most advanced engineering masterpieces of the 21st century,

just as temples were thousands of years before,

built for the gods of their epoch

by engineers who can not have known their achievements

would still be admired thousands of years later.

Temple engineering has left a legacy for the modern world

whether in the designs for large imposing buildings

or in the construction techniques used every day.

The ancients imagination and ambition

push the boundaries of what was possible

to create awe inspiring marvels

from the spectacular slabs of Stonehenge

to the towering columns of Karnak

and the grandeur of the Pantheon stone,

enduring testaments to the genius of ancient engineers.

[dramatic music]