Original subtitles

NARRATOR:It's one of the most magnificent cities of the ancient world:

Petra.

Its monumental temple-like tombs soar over 100 feet tall.

And these wonders of engineering are not constructed;

they're carved out of sandstone cliffs.

At its height, Petra was thecenter of a vast trading network

in frankincense and myrrh and home to over 30,000 people

in one of the most bone-dry deserts on earth.

UELI BELLWALD:It's not an appropriate location for a city.

There is not even drinking water down there.

NARRATOR: How did an ancient people

supply enough water for this vast city?

And how did they carve these magnificent structures

so high up in these cliffs?

To find out, a geoscientist teams up with stonemasons

to carve a Petra-style tomb.

TOM PARADISE: We're looking at something that hasn't been witnessed

for almost 2,000 years.

NARRATOR: And archaeologists and hydro-engineers

discover how a group of nomads

transformed this desert city into an oasis,

the Las Vegas of the ancient world.

LEIGH-ANN BEDAL: It's really conspicuous consumption

of this precious resource, water,

in this desert environment.

NARRATOR: Finally, after 2,000 years,

the secrets of Petra are about to be revealed.

Up now on NOVA, "Petra: Lost City of Stone."

NARRATOR: It's one of the driest places on Earth.

(camel grunting)

Yet concealed among the canyons of this harsh desert

in the Kingdom of Jordan is a magnificent ancient city:

Petra.

For over a thousand years, its location remained hidden,

protected by fortress-like cliffs

and Bedouin tribeswho fiercely guarded its secret.

Then, in 1812,

a Swiss adventurer disguised as an Arab pilgrim

risks his life to search for the legendary city.

Johann Ludwig Burckhardt makes his way through the Siq,

a dramatic canyon rising almost 600 feet

that twists and turns for nearly a mile.

Near its end, the canyon widens

to reveal a towering temple-like facade.

It is called the Treasury, or "Khazneh" in Arabic.

Built 2,000 years ago,

it is a masterpiece of design and engineering.

Majestic columns rise from the canyon floor,

topped by ornately carved capitals.

Statues of mythological figures adorn its facade.

A fanciful urn graces its roof.

And a towering doorway leads inside

to a room with three chambers.

Here, there is no elaborate carving,

just the simple, natural beauty of the stone.

And then we back away and we realize

not only is this building unique and fantastic,

but it has been carved into the sheer face of living rock.

NARRATOR: The Treasury is actually a sculpture

on a monumental scale.

At 80 feet wide and 127 feet tall,

it is twice the height of the Mt. Rushmore memorial.

As Burckhardt continues through the canyon,

he discovers hundreds

of magnificently carved facades everywhere,

many rivaling the grandeur of Egypt, Greece, and Rome.

But there is more: the ruins of an entire city.

A 6,000-seat theater carved right out of the sandstone,

a main street lined with huge temple-like structures,

and even more spectacular monuments

carved higher in the mountains.

But Burckhardt's rediscovery of the legendary city

sparks more questions than answers.

Who built Petra, and why?

Burckhardt was inspired by stories

of a mysterious desert tribe

who gained their wealth trading spices and silks

among China, India, Egypt, and Rome,

and then hid their treasures of gold in the cliffs.

Greek and Roman sourcesprovide a name for these people:

the Nabataeans.

An account from the 4th century BCE

describes the Nabataeans as nomadic tent-dwellers.

But three centuries later, another source describes them

as a sophisticated people inhabiting a prosperous city.

Around the time of Jesus,

Nabataea is a thriving kingdom surrounded by Egypt, Judea,

and the vast North Arabian Desert.

How, in just a few centuries,

did a village of tents become a wealthy kingdom?

And how, in the middle of a desert,

did they build Petra?

Tom Paradise has spent over three decades

trying to find out.

He is a geoscientist

who specializes in preserving ancient structures.

Alongside the Treasury, he sees strange square marks

that could be a clue to how it was built.

Are these marks the remnants

of where an ancient scaffoldwas anchored to the cliff face?

PARADISE: For many years, people considered these to be holds

for wooden scaffolding that may have been used

for the actual carving.

NARRATOR: But Paradise has doubts.

If these are scaffolding marks,

why did the Nabataeans leave them here?

And why are they found nowhere else in Petra?

Paradise believes the real reason for the marks

may be tied to the fanciful name

given to this monument centuries ago.

PARADISE: This building is calledthe Khazneh, it is the Treasury,

and so legend goes back millennia

that this housed riches.

NARRATOR: Because it is known as the Treasury,

people have searched it for treasure.

Bullet holes riddle the urn at the top,

and these marks may be footholds

to climb up and get a closer look.

We think maybe those footholds were carved

for the purpose of raiding the upper parts of the Khazneh

looking for the treasure.

NARRATOR: But the urn holds no gold; it's solid rock.

The only treasures here are the magnificent sculptures.

Whatever the true purpose of these marks,

Paradise is certain they're not for scaffolding.

After all, in this desert, wood is relatively scarce.

So how on earth could the ancient Nabataeans

carve such a huge monument so high up in the cliff face

without scaffolding?

Paradise has a bold plan to find out.

That go all the way downto the top...

NARRATOR: Working with a team of stonemasons,

they will try to carve a Nabataean-style facade

for the first time in 2,000 years.

PARADISE: I may be sitting on the answer to the age-old question

as to how were these facades carved.

NARRATOR:At the same time, archaeologists and hydro-engineers

are investigating how the Nabataeans could even survive

in this bone-dry environment.

BELLWALD: The entire hydraulic infrastructure was built,

as I think I may prove, following one master plan.

NARRATOR:Their groundbreaking discoveries

are revealing the engineers of Petra

were not only masters of stone, but also of water,

transforming a desert city

into the Las Vegas of the ancient world.

Now, can scientists finally uncover

how a nomadic tribe built this city of stone,

and why Petra ultimately vanished into legend?

("Indiana Jones" theme playing)

NARRATOR: Most people will recognize the Treasury

from the climactic scene

ofIndiana Jones and the Last Crusade,

where Harrison Ford and Sean Connery

enter a secret temple to discover the Holy Grail.

But despite the great Hollywood story,

the Treasury and most of Petra's iconic buildings

are not temples; they're tombs.

The Nabataeans left very little writing,

but on some of their facades are inscriptions

in an Aramaic script, the common language

of the Middle East in the time of Jesus.

This one, on a facade called Turkmeniya, reads in part,

"This tomb is sacred.

"Nothing of all that is inside

shall be changed or removed forever."

Tomb raiders disregarded notices like this,

so human remains and grave goods rarely survive.

But body-sized niches leave no doubt

these were burial chambers.

In all, the cliffs of Petra hold over 800 tombs.

CHRISTOPHER TUTTLE: The prominence of these monuments

led many of the early explorers to consider the possibility

that this might just be a city of the dead, a necropolis.

But over the past 200 years,

all of the research has actually shown

it was a city of the living as well.

NARRATOR: Chris Tuttle has been working here for more than ten years.

Although less than two percentof the site has been excavated,

archaeologists have mapped and surveyed the area.

All in all, ancient Petra was a metropolis

about the size of the island of Manhattan.

There is a two-square-mile downtown

where people lived, worked, and prayed.

Suburbs housing more peoplestretch to the north and south.

Based on these surveys, Tuttle can estimate the population.

TUTTLE: At its height, we expect this city

housed somewhere between 20,000 or 30,000 people.

NARRATOR: Yet unlike cultures that bury their dead in isolated areas,

in Petra, tombs are everywhere.

Why did the Nabataeans carvetheir tombs throughout the city?

And how did they do it?

Paradise hopes his carving project

will provide some answers.

PARADISE: Creating an experimentin which we reconstruct a facade

will give us insight into how the Nabataeans

carved these fantastic facades 2,000 years ago.

NARRATOR: But Paradise can't carve his facade here.

Petra is a protected World Heritage site.

He must find a cliff face

with the right kind of sandstone somewhere else.

His search takes him a world away,

to Southern California.

NATHAN HUNT: This looks like a promising prospect.

NARRATOR: While the ocean view is a sharp contrast

to the Jordanian desert,

the sandstone is identical to Petra's.

Paradise enlists stonemasons Blake Rankin and Nathan Hunt.

With permission from the landowner,

they search for just the right rock.

Hunt is a classically trained master carver

and architectural sculptor with over 18 years of experience.

We're looking for a fine-grained sandstone

which lends itself to ornamental carving.

NARRATOR: Sandstone is a soft rock

made of compressed layers of sand and minerals.

RANKIN: That looks like the type of stone we're looking for.

Yeah, this is great.

It looks like it's going to carve really well.

NARRATOR: The team has foundthe perfect rock and cliff face.

Now, they must find the right tools for the job.

Back in Petra, Paradise discovers a clue in the stone:

chisel marks made from iron tools.

PARADISE: The technologies used with chisels in stonework

haven't changed in 2,000 years.

We use the same chisels,

and so they leave the same marks.

NARRATOR: By matching modern day tool marks

with those found in Petra, their adviser Tom Paradise

tells them exactly which tools to use:

the claw chisel,

the flat chisel,

and the pointed chisel.

PARADISE: The pointed chisel is used for the coarser chiseling

that removes large amounts of rock.

NARRATOR: So the pointed chisel

is exactly what Hunt and Rankin use to begin work.

RANKIN: Yeah!

It feels good to be carving.

NARRATOR:But their exuberance fades fast.

Carving by hand is seriously slow.

HUNT:There's no waywe can do it by hand.

NARRATOR: A Greek source says the Nabataeans had few slaves,

but they probably did have

plenty of skilled manpower and time.

Hunt and Rankin have neither, but they have power tools.

Even so, Rankin insists they're not cheating.

RANKIN: This is a chisel very similar to one

that the Nabataeans would have used.

The only difference is that

we've mechanized the hammer process

so that we can move a lot of stone really quickly.

NARRATOR: The carvers have found the right rock

and the right tools for the job.

As Hunt and Rankin prepare the cliff face,

Paradise must decide what exactly to carve.

What makes a Nabataean tomb Nabataean?

Many of the facades in Petra

actually look like they belong somewhere else.

At the Treasury, Paradise finds statues, columns, and capitals

reminiscent of ancient Greece and Rome.

And across Petra,

he finds architectural features from other far-flung empires:

a step design associated with Assyria and Mesopotamia,

elephant-headed capitals evoking India,

even Egyptian obelisks.

But among the familiar

are designs Paradise has seen nowhere else.

PARADISE: There's a pediment at the top that is split in the middle,

capped by a cone, a capital, and an urn at the top.

This isn't Greek, this isn't Roman.

NARRATOR: This new design is seamlessly mixed

with features from far-off cultures.

PARADISE: The architecture is this synthesis.

And this begins to tell usa story that is the real Petra.

NARRATOR: What makes a Nabataean tomb Nabataean

is the combining of their own unique style

with designs from other empires.

But how did these people in the middle of the desert

come into contact with such faraway places?

Two words: frankincense and myrrh.

Frankincense and myrrh

were must-have luxury items in antiquity.

In the New Testament, they are among the gifts

the Three Kings bring to the baby Jesus.

Made from dried sap from trees

in the southern Arabian peninsula,

they were burned obsessively in religious ceremonies

in Egypt, Greece, and Rome.

But to get that incense to consumers

throhout the Mediterranean,

it first had to be transported through the desert.

After centuries of living as nomads,

the Nabataeans knew every secret source of water.

If you wanted to cross the desert

and make it out alive,you had better have a Nabataean

leading the way.

(camel grunting)

Along the route, they built outposts

to guard their goods and extract a toll.

In a valley just over the mountain from Petra,

Andrew Smith has excavated this fort called Bir Madhkhur.

ANDREW SMITH: There was definitely a Nabataean presence here,

most likely related to the trade that came out of Petra.

NARRATOR:Among the artifacts he excavated

are dozens of tiny clay perfume bottles.

The Nabataeans were most likely processing

some of the raw frankincense,

and they would have bottled and then packed them tightly

so that they weren't going to break

and probably loaded them on camels or even donkeys.

NARRATOR: The Incense Road becamethe lifeblood of the Nabataeans,

pulsing from Saudi Arabia to the port of Gaza,

the gateway to Greece and Rome.

The financial reward from this trade

catapults a desert tribe into a powerful kingdom.

Nabataean towns and tombs spring up

throughout the northwestern Arabian peninsula.

By the first century, the Roman writer Pliny

called the Nabataeans "the richest race on earth."

Much of their wealth

went into building their capital city, Petra.

Tom Paradise believes

the Nabataeans' far flung trade connections

influenced their domestic designs.

PARADISE: Because Petra is a crossroads for the region,

it makes sense that they would adopt and adapt

different architectural styles

from a lot of their trading partners.

NARRATOR: But with all these different styles,

what should Paradise pick for his carving experiment?

PARADISE: This sort of facade represents

more than 500 other facades in Petra.

So this style really is the archetype of the tomb facades.

NARRATOR: To Paradise, this tomb is typically Nabataean.

Although it appears plain,

it's a mash-up of different architectural styles.

It has the remains of a Greco-Roman doorway,

Nabataean capitals, an Egyptian cornice,

and a design from Assyria

that may represent a stairway to heaven,

called a crow step.

But when the carving team

transfers the design to California,

it isn't wide enough to fit the rock.

You never really know how it's going to work

in the stone until you get started.

We think it's going to look a lot better

if we widen the facade.

NARRATOR: But how will making the facade wider affect the design?

Make each block of the crow step seven by seven inch.

This would be the edge of the crow steps.

RANKIN:That would be great.

NARRATOR: Grappling with this problem, the team may shed light

on a mystery that has confounded scholars for decades.

Why do Nabataean tbs, while similar,

have unique variations?

PARADISE: There is one motif they modify a lot,

and that is the crow step.

Why the differencewe have never really understood.

NARRATOR: Some of the tombs in Petra have crow steps

that reach all the way down to a narrow ledge

called the cornice.

Other crow steps meet in the middle.

Some scholars have argued thisreflects an evolution in design.

But Paradise thinks they havestruck upon a practical reason.

As we make the facade wider, it really requires us

to take the crow stepsall the way down to the cornice.

NARRATOR: If the facade is wider,the crow steps must break apart.

PARADISE: Increasingly, we notice that changes of the rock

actually caused changes within the design elements.

I think we have to givemore credit to the rock

than we have in the past.

Just sort of roughly marknine inches on there.

NARRATOR: By carving their own facade,

they discover a basic principle of Petra:

the rock influences what they carve

and where they carve it.

But why here?

Choosing to build their capitalin the middle of a rocky desert

poses another age old question:

how did the Nabataeans get enough water

to support such a magnificent city?

One clue is here, in the city center,

at a structure known as the Great Temple.

Its monumental stairwayleads to a large stone platform

surrounded by over a hundred columns.

Holes in the courtyard show

there are channels running underneath it.

It's runningunder the floor.

SUE ALCOCK: Oh, that'll do it.

NARRATOR: Sue Alcock leads a team

from Brown University to investigate.

ALCOCK: If we could make all this surface architecture go away,

you know, just kind of magically

lift it up and look down, I think we would see

quite a network of these channels and canals.

NARRATOR: She may be sho on magic,

but Alcock does have another way to look below the surface:

a technology called GPR-- ground-penetrating radar.

TOMMY URBAN: Excavation is inherently destructive.

This is a way to get a look at what's down there

in the same way you would go in for an x-ray perhaps

before you went in for a surgery.

NARRATOR:The radar sends a high-frequency radio wave into the ground.

When the wave passes through different materials,

like from stone to soil,

part of the wave is reflected back.

But the speed of the wave changes

depending on the material:

slower for soil, faster through air.

Detecting these changes

is how the GPR sees where the channels are.

The team systematically drags the radar

back and forth across the courtyard.

URBAN: There's some kind of a channel right there.

ALCOCK:Oh yeah, look at that.

NARRATOR: Beneath the Great Temple

is a network of channels that looks like plumbing.

Intriguingly, the channels seemto extend beyond the courtyard.

ALCOCK: When we look at Petra,

we often tend to think about building by building,

and actually, I think it was all tied together.

NARRATOR: Alcock believes these channels are evidence

of a massive city-wide water system.

Petra was an urban center, and it had urban water supply.

NARRATOR: There's just one problem with this theory.

Petra is in one of the driest places on the planet.

If the Great Temple

is indeed the heart of a vast engineering system

that supplied an entire city with water,

where is all that water coming from?

One possible source is still used daily by locals.

It's called Ain Musa, or the spring of Moses.

Allison Mickel and Cecelia Feldman

of Brown University's survey team

join hydro-engineerCharles Ortloff to investigate.

CECELIA FELDMAN: In Numbers 20:11,

it talks about how the Israelites

were wandering in the desert.

And Moses strikes this rockin anger, and water flows forth.

NARRATOR:The story of Moses miraculously bringing forth water

has been linked in legend to this rock and spring.

But it would take an engineering miracle

to get this water from Ain Musa to Petra's city center--

it's five miles away.

In the Siq, the entrance to Petra,

the team finds evidence

for how the water may have been brought here.

Running along the sideof the path is a narrow channel

which has imprints of what were once enclosed ceramic pipes.

CHARLES ORTLOFF: If you look inside of the channel,

you can see the actual imprints of ceramic sections

that are roughly about a third of a meter long.

NARRATOR: At roughly a foot long,

it would require tens of thousands of segments

to create a five-mile pipeline from Ain Musa,

high in the mountains.

And every one of those joints

would have the potential to spring a leak.

Could the Nabataeans possibly have pulled off

such a feat of hydro-engineering?

At California State University in San Jose,

Charles Ortloff and graduate student Shayan Mizrahosseini

are trying to figure that out using this 26-foot tank.

Water is extremely precious to the Nabataeans,

so ancient engineers

needed to design a pipeline that would be free of leaks.

NARRATOR:Their challenge, and Ortloff's,

is how to get water to flow through a pipe

as quickly and efficiently as possible.

The different anglesrepresent different choices.

NARRATOR: One choice seems obvious:

make the slope of the pipe steep.

Ortloff sets the slope to six degrees

and turns on the water.

Things start out well.

The water is flowing fast.

But it fills the pipe too quickly,

producing an area of turbulence known as a hydraulic jump,

which causes the water flow to slow down.

ORTLOFF: This is the hydraulic jump, right here.

NARRATOR: But there's a bigger problem:

the pipe is now filled with water,

raising the pressure.

In the ceramic pipelines,

that pressure could create leaks at the joints.

ORTLOFF: So that design,where we have the steeper slope,

is not good.

SHAYAN MIZRAHOSSEINI: Okay, closing all the valves.

ORTLOFF: If you can put the brick on the other side,

we're just going to slide it over.

NARRATOR: Ortloff adjusts the slope of the pipe to four degrees.

A little more.

There we go.

Got it.

NARRATOR: A small change in the slope, just two degrees shallower,

has a big impact on the speed of the water.

ORTLOFF:The big surprise here is thatwe have only changed the slope

by two degrees,

and yet we have a completelydifferent flow pattern.

NARRATOR: The flow is fast.

And in this test, the pipe never completely fills with water,

which would be good news for Petra's plumbers.

ORTLOFF: The entire flow has an exposed air space above the surface,

and this will prevent leakage in the system.

NARRATOR: With the help of modern day tools,

Ortloff has shown that the best design

for delivering water fast and leak-free

is a four-degree slope.

And when Ortloff measures the angle

of the carved channel in Petra,he makes a remarkable discovery.

ORTLOFF: If we look at actual field measurements,

we're able to see that with their pipeline,

the ancient Nabataean engineers

had a slope of approximately four degrees.

NARRATOR: 2,000 years ago,

Petra's engineers worked out the perfect design

for their long-haul pipelines.

ORTLOFF: They invented scientific principles

that were only officially discovered in the West

some 2,000 years later.

NARRATOR:It is clear that the Nabataeanswere master hydraulic engineers.

But water is not the only scarce resource in the desert.

Wood from local trees was also in short supply.

So how could the Nabataeans build their tombs

so high up in the cliff face

without using large wooden scaffolding?

Paradise finds an important clue in this unusual carving,

aptly called "The Unfinished Tomb."

The top is finished.

The upper area of the capitals remains somewhat crude

and still in progress.

But then below that,nothing has been carved at all.

It's the natural sandstone face.

NARRATOR: To Paradise, the progression of finished at the top

and barely started below can mean only one thing.

The Nabataeans started from the top and carved down.

NARRATOR: The unfinished tomb shows that Nabataeans began

by sculpting the top layer of the facade,

and then worked their way down the cliff face.

Getting windy again.

Yep.

NARRATOR: Back in California, Paradise tells Hunt and Rankin

they must carve their facade Nabataean style:

top down and without scaffolding.

HUNT: There's a lot of challenges involved

in trying to figure out how the Nabataeans

carved a piece like this.

I die like a Nabataean is my worst fear.

(laughing)

Falling off the rock.

NARRATOR: Up to now, they've been using safety harnesses.

But the Nabataeans' top-down approach

gives them an ingenious idea for how to carve

without harnesses or a large wooden scaffold.

RANKIN: We've drilled into the stone here

and placed a couple of pins and then put a plank on top

and created a temporary and movable ledge

that doesn't require a lot of material.

NARRATOR: They drive three pins into the rock

and lay just a couple of planks of wood across them,

forming a platform.

As their carving descends,

it erases the holes they've made,

leaving no sign of their platform.

By the time we get to the bottom,

we've pretty much removed all evidence of any plank.

NARRATOR: The pin and plank solution works perfectly.

It could explain how the Nabataeans

were able to carve so high up without scaffolding,

and why no evidencefor the technique can be found.

Halfway through the carving,

the team makes another discovery.

RANKIN: We can move a lot of stone really quickly

with these chisels.

We've been moving a surprising amount of stone every day.

NARRATOR: A little carving creates a lot of rubble.

I really cannot believethat much carving

produced this much rubble.

NARRATOR: The rubble has formed a ramp.

This means they don't need their platform anymore.

Now they can just walk up to the façade.

PARADISE: When we see this much materialbeing produced from the carving,

we now realize that we create ramps from this rubble

that gives you access to the facade for the stone carvers.

NARRATOR: Combining the clues found in Petra

with the discoveries in the carving project,

a new theory emerges

for how the Nabataeans may have carved the Treasury.

They begin by climbing to the top.

Here, they cut a narrow ledge into the cliff face.

Using ancient drills, they fix pins below the ledge

and lay planks across to provide a platform for the carvers.

The first thing they carve is the urn,

and the upper layer of the monument.

They work their way down,

sculpting the split pediment and the magnificent statues.

About halfway down, the debris from the carving forms a ramp.

Now the carvers can walk up to theacade

and continue carving the elaborate capitals

and the handsome columns.

We don't knowof any other culture or society

using this kind of engineering technique

for this scale of construction.

NARRATOR:The top-down approach turns out to be a brilliant innovation

for carving these tombs in Petra's sandstone cliffs.

But carving is only part of the Treasury's grandeur.

Its impressive locationcommands the head of the canyon

and the entrance to the city.

Yet the same narrow canyon that creates this dramatic reveal

can also be a death trap.

These amateur videos capturea rare but deadly desert hazard:

flash floods.

Petra's average annual rainfall of just a few inches

can hit all at once

and pour down this gorge with lethal force.

Flash floods took the lives of22 French tourists here in 1963,

and even today could damage the Treasury.

Ueli Bellwald, a Swiss architect and archaeologist,

has come to Petra to protectboth tourists and the Treasury.

He's searching for clues to how the Nabataeans

held back the floods.

BELLWALD: When they decided to carve this facade into the cliff,

they had to do something against flash floods in wintertime.

NARRATOR: Next to the Treasury is a narrow gorge.

Here, Bellwald finds huge blocks mortared together

to form an ancient dam.

BELLWALD: It's 2,000 years old

and still totally preserved.

NARRATOR: But this one dam would not beenough to protect thTreasury,

so Bellwald is on the hunt for more dams.

While the landscape appears to be plain rock,

to Bellwald, it is packed with clues.

He notices different colors on the canyon wall.

Above this line, the stone is dark.

Below, it's lighter,

which Bellwald believes is caused by mineral deposits

from water once stored here in a reservoir.

Following this water line brings him to an area

where two deep grooves have been carved into the canyon walls.

The grooves show where a dam once stood.

BELLWALD: All of these dams had to be anchored

into the cliffs on both sidesthat they could easily withstand

the pressure of the retained water.

NARRATOR: Following these clues,

Bellwald has uncoveredan ancient Nabataean dam system.

The Nabataeans built five dams.

And to make those dams even more effective,

they carved a channel 140 feet long and 16 feet deep

to reroute some of the water.

This created a large area to store overflow

and reduce the force of the water

before it reached the Treasury.

It's an engineering feat

almost as impressive as the Treasury itself.

BELLWALD: They realized that if they divert the water,

they allow the water to spread out to a much bigger surface.

And this reduced its speed tremendously.

It worked perfectly.

NARRATOR: So perfectly, Bellwald can't improve on this design.

Today, a team is repairing this ancient dam network

so it can once again protect the Treasury.

BELLWALD:If we want to keep the Treasury for the future,

we have to protect it again as 2,000 years before

from flash floods.

And that's exactly what I'm doing.

NARRATOR: Because the threat of floods was so great,

Bellwald believes the Nabataeans must have built the dam system

and the Treasury at the same time.

In fact, scholars now believe the grand tombs,

the city center, and the water systems--

most of the ancient city of Petra--

were built within 100 years around the birth of Jesus.

BELLWALD: The entire hydraulic infrastructure of Petra

was built following one master plan.

NARRATOR: So just how much water did that system provide?

Back in San Jose, Charles Ortloff is figuring that out.

These are the main supplies of water

from all of the cisterns,all the dams.

NARRATOR: Ortloff has mapped every water feature

he and other archaeologists have discovered:

eight springs for fresh drinking water,

36 dams to protect the city from flash floods,

over 100 cisterns and reservoirs to collect and hold rainwater,

and 125 miles of pipeline

to connect many of these features

into one integrated water system.

From the map and his flume experiments,

Ortloff can estimate the total amount of water available

to Petra's 30,000 people.

If you sum up all of the water from various sources,

that would lead to eight liters per person per day.

NARRATOR: Eight liters is about two gallons.

In a world before showers and washing machines,

that's more than enough water to survive on.

In fact, new discoveries reveal that the Nabataeans

had enough water to transform Petra into a desert oasis.

Evidence of that water surplus is being found

right next to the Great Temple, in a large open terrace.

It was named by early explorers as the Marketplace,

so when Leigh-Ann Bedal began digging here in 1998,

that's what she expected.

LEIGH-ANN BEDAL: Because it had been called a marketplace,

I came in prepared to excavate a market.

NARRATOR: But as she began digging, at eight feet deep,

she discovered waterproof cement.

BEDAL:So we knew that we had something containing water,

something deep.

NARRATOR: Her team excavated further

and discovered a subterranean structure.

BEDAL: We have the southwest corner here,

and directly to the north is the northwest corner.

NARRATOR: Bedal located all four corners

to discover overall dimeions of 140 by 80 feet,

nearly the size of an Olympic swimming pool.

Then, in the middle,

she found evidence of a stone platform

and surroundingthe sunken structure, channels,

likely used for irrigating a lower terrace

where soil samples suggest the area had been cultivated.

When she puzzles the evidence together,

Bedal concludes the marketplace

was in fact a huge ornamental pool complex

including an island pavilionand a garden on a terrace below.

BEDAL: If you could imagine below us

this large pool of water and then a green garden

with date palm trees and flowers.

This is something that is for showing off.

NARRATOR: Throughout the city center, archaeologists are finding

other decorative water features like fountains,

and a canal running beside a colonnaded street.

It's really conspicuous consumption

of this precious resource, water,

in this desert environment.

NARRATOR:Conspicuous consumption of water in the middle of a desert?

It seems Petra resembled another flashy desert destination.

BEDAL:A great comparison is Las Vegas,

where you have this very arid desert

surrounding this oasis city, where everywhere you go,

you see the use of water, fountains.

By diverting a precious resource into a wealthy center,

it sends a message to anybody who sees it

that it is a place of wealth and power.

NARRATOR: For ancient visitors,

after days of traveling on camelthrough the hot, parched desert,

entering this oasis city musthave made a powerful impression.

Petra's luxurious pools

and internationally inspired architecture

likely sparked the legends that echoed through the ages.

Back iCalifornia,

after two months of carving and nearly 2,000 years,

architecture of far-off lands emerges from the rock.

PARADISE: We've got Assyrian, Egyptian, Greco-Roman,

but you put it together,

you stand backand it's Nabataean.

And now it's a little bit Californian.

That's right.

NARRATOR: Whether the Nabataeans were carving tombs for the dead

or water channels for the living,

their mastery of stone

was the key to Petra's wealth and beauty.

So why did the Nabataean kingdom decline

and Petra largely disappear?

Across the city,

collapsed columns point to a prime suspect:

ancient texts record a huge earthquake in 363.

ALCOCK: As a result, for a while,

when archeologists came to Petra,

any time they saw something like this, they would say,

"Ah, this fell down in 363."

NARRATOR:But one catastrophic earthquake

does not provide the whole picture of the city's decline.

At the Great Pl, the most luxurious place in Petra,

there's evidence that hard times hit the city even earlier.

BEDAL: It may have been as early as the second century,

because at that point,

we find a lot of animal bones at the bottom of the pool,

so it seems to have been used for trash.

NARRATOR: Found in the great pool,

this layer of fallen rocks dates to around the 363 quake.

But below that,

the layer of soil containing the animal bones

indicates the pool filled in at least 100 years before.

And there is evidence of more destruction

100 years after the great quake,

which may have fatally weakened the city's protective dams.

Large sections of Petra'smain street are missing pavers.

Tom Paradise believes they were washed away

in a catastrophic flash flood.

PARADISE: The floodwaters rushed down through Petra's city center,

ripping up cobblestones.

This flood inundated the city

and may have marked the end of Petra's golden age.

NARRATOR: Ironically, the very water that brought life to Petra

may also have contributed to its demise.

Today, in the hills of Southern California,

the carving team is bringing a bit of Petra back to life.

The final flourish

will be a feature not found in other cultures:

a Nabataean-style capital

with a simple knob in its cter.

Normally, there is a detail here.

Typically, there is a leaf or a flower here.

You never really see it left in this very abstract form.

It's quite beautiful in its splicity.

NARRATOR:Paradise believes the Nabataeans

choose this simple form out of respect,

almost reverence, for the sandstone.

PARADISE: Their sense of the rock as a living material

that had to be sort of caressed and worked

was really as remarkableas their engineering expertise.

NARRATOR: And the sandstone itself becomes a tool

to finish the surface of the tomb.

HUNT: I'm using the same stone that we carved off the rock.

I'm just rubbing the last little stages,

just kind of carefullyfinishing off that last surface.

NARRATOR: Stone is at the core of Nabataean lives.

The very name for their city, Petra,

comes from the Greek word for rock.

PARADISE: The Nabataean relationship with their sandstone

was fundamental to who they were.

They're born in this valley of rock,

they live in this valley of rock,

and then when they die, they are buried in the rock itself.

These hewn tomb facades become their final resting place.

NARRATOR: Each year, over half a million tourists retrace the steps

of the explorer Johann Ludwig Burckhardt

and gaze up in awe at the Treasury.

But in the two centuries

since Petra was re-opened to the Western world,

its distinctive engineering and culture

is proving equal to that of any ancient civilization.

TUTTLE: Petra is more than a city.

It was the seat of a kingdom,

a kingdom whose peace and prosperity

was the envy of the ancient world.

NARRATOR: Cisterns, channels, dams, even fountains and pools.

The Nabataean mastery of water

fueled their astonishing city of stone.

ALCOCK: The water features are underpinning everything.

If the Nabataeans

couldn't control the water, you wouldn't have a city here.

NARRATOR: Over 2,000 years ago,

a desert tribe settled among these forbidding cliffs

and transformed this hostile landscape into an oasis.

PARADISE: The Nabataeans learned how tomaximize these limited resources

to produce a society and a culture

that thrived and prospered forhundreds and hundreds of years.

NARRATOR: Burckhardt came here chasing legends of a city

lost in the sands of the desert.

A city with riches from all over the known world,

buildings that rivaled Egypt and Rome,

and fountains and pools overflowing with water.

Today, it's clearmany of the legendary splendors

of the lost city of Petra are true.

The story continues online,

♪

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