Nova (1974–…): Season 42, Episode 5 - Petra: Lost City of Stone - full transcript

Is 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 the
center 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.

It's not an
appropriate location for a city.

There is not even drinking water
down there.

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.

We're looking at something
that hasn't been witnessed

for almost 2,000 years.

And archeologists
and hydro-engineers

discover how a group of nomads

transformed this desert city
into an oasis,

the Las Vegas
of the ancient world.

It's really
conspicuous consumption

of this precious resource,
water,

in this desert environment.



Finally, after 2,000 years,

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

Supporting NOVA and promoting
public understanding of science.

And the Corporation
for Public Broadcasting,

and by PBS viewers like you.
Thank you.

It's one of the driest places
on Earth.

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 tribes
who 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 carve into
the sheer face of living rock.

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?

Burkhardt was inspired by stories
of a mysterious desert tribe

who gained their wealth
trading spices and silks

among Chine, India,
Egypt and Rome.

and then hid their treasures
of gold in the cliffs.

Greek and Roman sources
provide 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 scaffold
was anchored to the cliff face?

For many years, people
considered these to be holds

for wooden scaffolding
that may have been used

for the actual carving.

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.

This building is called
the Khazneh, it is the Treasury,

and so legend goes back
millennia

that this housed riches.

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.

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 down
to the top...

Working with a team
of stonemasons,

they will try to carve
a Nabataean-style facade

for the first time
in 2,000 years.

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

as to how were these facades
carved.

At the same time, archaeologists
and hydro-engineers

are investigating how the
Nabataeans could even survive

in this bone-dry environment.

The entire hydraulic
infrastructure was built,

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

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?

Most people
will recognize the Treasury

from the climactic scene

of Indiana 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
Turkmaniya, 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.

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.

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

Although less than two percent
of 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

were people lived, worked,
and prayed.

Suburbs housing more people
stretch to the north and south.

Based on these surveys, Tuttle
can estimate the population.

At its height,
we expect this city

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

Yet unlike cultures that bury
their dead in isolated areas,

in Petra, tombs are everywhere.

Why did the Nabataeans carve
their tombs throughout the city?

And how did they do it?

Paradise hopes
his carving project

will provide some answers.

Creating an experiment
in which we reconstruct a facade

will give us insight
into how the Nabataeans

carved these fantastic facades
2,000 years ago.

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.

This looks like a promising
prospect.

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.

Sandstone is a soft rock

made of compressed layers
of sand and minerals.

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.

The team has found
the 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.

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.

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.

The pointed chisel is used
for the coarser chiseling

that removes
large amounts of rock.

So the pointed chisel

is exactly what Hunt
and Rankin use to begin work.

Yeah!
It feels good to be carving.

But their exuberance fades fast.

Carving by hand
is seriously slow.

There's no way
we can do it by hand.

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.

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.

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.

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.

This new design
is seamlessly mixed

with features
from far-off cultures.

The architecture
is this synthesis.

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

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

throughout 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.

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.

There was definitely
a Nabataean presence here,

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

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.

The Incense Road became
the 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 riches 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.

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.

But with all these
different styles,

what should Paradise pick
for his carving experiment?

This sort of facade represents

more than 500 other facades
in Petra.

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

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,

Nabataeans 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.

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.

That would be great.

Grappling with this problem,
the team may shed light

on a mystery that has confounded
scholars for decades.

Why do Nabataean tombs,
while similar,

have unique variations?

There is one motif
they modify a lot,

and that is the crow step.

Why the difference
we have never really understood.

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 this
reflects an evolution in design.

But Paradise thinks they have
struck upon a practical reason.

As we make the facade wider,
it really requires us

to take the crow steps
all the way down to the cornice.

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

Increasingly, we notice that
changes of the rock

actually caused changes
within the design elements.

I think we have to give
more credit to the rock

than we have in the past.

Just sort of roughly mark
nine inches on there.

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 capital
in 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 stairway
leads to a large stone platform

surrounded by over
a hundred columns.

Holes in the courtyard show

there are channels running
underneath it.

It's running
under the floor.

Oh, that'll do it.

Sue Alcock leads a team
from Brown University to investigate.

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.

She may be sho on magic,

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

a technology called GPR--
ground-penetrating radar.

Excavation is inherently
destructive.

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

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

before you went in
for a surgery.

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.

there's some king of a channel
right there.

Oh yeah look at that.

Beneath the Great Temple

is a network of channels
that looks like plumbing.

Intriguingly, the channels seem
to extend beyond the courtyard.

When we look at Petra,

we often tend to think about
building by building,

and actually, I think
it was all tied together.

Alcock believes these channels
are evidence

of a massive city-wide
water system.

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

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-engineer
Charles Ortloff to investigate.

In Numbers 20:11,
it talks about how the Israelites

were wandering in the desert.

And Moses strikes this rock
in anger, and water flows forth.

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 side
of the path is a narrow channel

which has imprints of what were
once enclosed ceramic pipes.

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.

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.

Their challenge, and Ortloff's,

is how to get water
to flow through a pipe

as quickly and efficiently
as possible.

The different angles
represent different choices.

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.

This is the hydraulic jump,
right here.

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.

So that design,
where we have the steeper slope,

is not good.

Okay, closing all the valves.

If you can put the brick
on the other side,

we're just going
to slide it over.

Ortloff adjusts the slope
of the pipe to four degrees.

A little more.

There we go.
Got it

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

has a big impact
on the speed of the water.

The big surprise here is that
we have only changed the slope

by two degrees,

and yet we have a completely
different flow pattern.

The flow is fast.

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

which would be good news
for Petra's plumbers.

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

and this will prevent leakage
in the system.

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.

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.

2,000 years ago,

Petra's engineers worked out
the perfect design

for their long-haul pipelines.

They invented
scientific principles

that were only officially
discovered in the West

some 2,000 years later.

It is clear that the Nabataeans
were 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.

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.

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.

Back in California,
Paradise tells Hunt and Rankin

they must carve their facade
Nabataean style:

top down
and without scaffolding.

There's a lot
of challenges involved

in trying to figure out
how the Nabataeans

carved a piece like this.

To die like a Nabataean
is my worst fear.

Falling off the rock.

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.

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.

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.

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 evidence
for the technique can be found.

Halfway through the carving,

the team makes
another discovery.

We can move a lot of stone
really quickly

with these chisels.

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

A little carving creates
a lot of rubble.

I really cannot believe
that much carving

produced this much rubble.

The rubble has formed a ramp.

This means they don't need
their platform anymore.

Now they can just walk up
to the facade.

When we see this much material
being 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.

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 the facade

and continue carving
the elaborate capitals

and the handsome columns.

We don't know
of any other culture or society

using this kind
of engineering technique

for this scale of construction.

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 location
commands 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 capture
a 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 of
22 French tourists here in 1963,

and even today
could damage the Treasury.

Ueli Bellwald, a Swiss architect
and archaeologist,

has come to Petra to protect
both tourists and the Treasury.

He's searching for clues
to how the Nabataeans

held back the floods.

When they decided to carve
this facade into the cliff,

they had to do something against
flash floods in wintertime.

Next to the Treasury
is a narrow gorge.

Here, Bellwald finds huge blocks
mortared together

to form an ancient dam.

It's 2,000 years old

and still totally preserved.

But this one dam would not be
enough to protect the Treasury,

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.

All of these dams
had to be anchored

into the cliffs on both sides
that they could easily withstand

the pressure
of the retained water

Following these clues,

Bellwald has uncovered
an 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.

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.

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.

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.

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.

The entire hydraulic
infrastructure of Petra

was built
following one master plan.

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.

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.

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.

Because it had been called
a marketplace,

I came in prepared
to excavate a market.

But as she began digging,
at eight feet deep,

she discovered
waterproof cement.

So we knew that we had something
containing water,

something deep.

Her team excavated further

and discovered
a subterranean structure.

We have the southwest
corner here,

and directly to the north
is the northwest corner.

Bedal located all four corners

to discover overall dimensions
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 surrounding
the 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 pavilion
and a garden on a terrace below.

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.

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.

Conspicuous consumption of water
in the middle of a desert?

It seems Petra resembled another
flashy desert destination.

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.

For ancient visitors,

after days of traveling on camel
through the hot, parched desert,

entering this oasis city must
have made a powerful impression.

Petra's luxurious pools

and internationally inspired
architecture

likely sparked the legends
that echoed through the ages.

Back in California,

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

architecture of far-off lands
emerges from the rock.

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

but you put it together,

you stand back
and it's Nabataean.

- And now it's a little bit Californian.
- That's right.

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.

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."

But one catastrophic earthquake

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

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

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

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.

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's
main street are missing pavers.

Tom Paradise believes
they were washed away

in a catastrophic flash flood.

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.

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 center.

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 simplicity.

Paradise believes the Nabataeans

chose this simple form
out of respect,

almost reverence,
for the sandstone.

Their sense of the rock
as a living material

that had to be sort of caressed
and worked

was really as remarkable
as their engineering expertise.

And the sandstone itself
becomes a tool

to finish the surface
of the tomb.

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

I'm just rubbing
the last little stages,

just kind of carefully
finishing off that last surface.

Stone is at the core
of Nabataean lives.

The very name for their city,
Petra,

comes from the Greek word
for rock.

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.

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.

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.

Cisterns, channels, dams,
even fountains and pools.

The Nabataean mastery of water

fueled their astonishing city
of stone.

The water features
are underpinning everything.

If the Nabataeans

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

Over 2,000 years ago,

a dessert tribe settled
among these forbidding cliffs

and transformed this hostile
landscape into an oasis.

The Nabataeans learned how to
maximize these limited resources

to produce a society
and a culture

that thrived and prospered for
hundreds and hundreds of years.

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 clear
many of the legendary splendors

of the lost city of Petra
are true.