All language subtitles for The UnXplained s08e06 Mighty Kingdoms Unearthed.eng

WILLIAM SHATNER:
Twisted cords concealing secrets

to an ancient mountain empire.

A quest of mythic proportions

carved into
a mysterious runestone.

And a universal ruler

intentionally hidden
for all eternity.

Throughout the course
of human history, many kingdoms

have prospered and expanded
their territory,

only to one day collapse
into the sands of time.

And with their demise,

secrets as to
how these cultures lived,

fought, and ruled
simply vanished.

Fortunately, tantalizing clues
left behind

offer historians
and archaeologists

the opportunity
to piece together

what remains
of the ancient past.

For instance, what can
an intricate gold artifact

from a mountain lake or
a towering megalithic pyramid

reveal about
the people who made them?

Well, that is what
we'll try and find out.

? ?

Perched precariously
on a mountaintop

nearly 8,000 feet
above sea level

lies an ancient city
that looks like

it's floating in the clouds.

Built around 1450 A.D., this
curious engineering marvel

stands as the crowning
achievement of the Inca Empire

and is known as Machu Picchu.

Machu Picchu
is a technological marvel.

For one thing,
it's a fairly good-sized city,

and it was built
at an incredibly high elevation.

And it's sculpted
into the mountains.

It takes a bit of time
to even get up there.

EDWIN BARNHART:
The moment you walk in, you think to yourself,

"How did anyone

build this
on top of sheer cliffs?"

It's a perilous journey.

The mountainside
is straight up and down.

And so, after climbing up
to this huge height,

you see that
the buildings themselves

seem to blend
into the landscape.

As an archaeologist
who has worked on sites

around the world
and seen incredible

engineering achievements,

Machu Picchu
kind of blows it all away.

We're talking massive,
multi-ton stones

shaped and moved into place,

and they fit together perfectly.

And this mountain site,
somehow, was transformed into

an enduring city
and survives 500 years later

in absolutely perfect condition.

SHATNER:
Perhaps the greatest mystery of Machu Picchu

is why did the ancient Incas
choose to build

a sprawling city

in such an inaccessible
mountain location?

SABINE HYLAND:
The Incas had a incredibly sophisticated culture.

We know that in the Inca Empire,
when a building was built,

it had to be made strong
in the spiritual world

as well as
in the physical world.

As you walk through,
you can see how the Inca artists

echoed the shapes of all the
mountains in the construction

of Machu Picchu in honor
of the mountain gods around it.

On the other hand, just saying
that only tells us a little bit.

There is still
a huge amount of mystery

about what Machu Picchu was for.

SHATNER: Some believe that Machu
Picchu's true purpose may be connected

to the great ruler
who ordered its construction,

Emperor Pachacuti.

Machu Picchu was built
by the Emperor Pachacuti,

who's known as, really,
the founder

of the Imperial phase
of the Inca state.

One thing to remember is that,
in the Inca Empire,

the emperors can...
were considered divine.

They were considered like gods.

And when an emperor died,
his body was mummified,

and it was treated
as if he was still alive

so that their
worship could continue.

And so, after Pachacuti's death,

his family would still
go and use Machu Picchu,

and we believe that
when they did so,

they brought the mummified body
of the emperor with them.

SHATNER:
Did Emperor Pachacuti build Machu Picchu

to be a sacred site
in the mountains,

where his mummy
could rest for all eternity?

It seems like
a reasonable theory,

but there's just one problem.

Pachacuti's remains
have never been found.

However, in recent years,

some have suggested
that the emperor's mummy

may be hidden in a
secret chamber at Machu Picchu.

In 2010, a French engineer
by the name of David Crespy

was doing some measuring work
within the city of Machu Picchu.

And he noticed what was
quite clearly a doorway,

blocked up by stones.
And it clearly

was blocking the entrance
into some kind of a chamber.

He reported it immediately
to the authorities,

and people have suggested
that this might well be

the entrance
into some kind of tomb.

We could be looking at
a royal burial.

So, is it
the tomb of Pachacuti?

HUGH NEWMAN:
Now, they did

more tests and more scans, and
they found what appeared to be

gold-lined steps
going down into this area.

They wanted to push forward
and excavate this,

because this would have been,

without doubt,
the most important discovery

ever found at Machu Picchu.

But then, apparently,
the Peruvian government

have kind of put a block on it

and stopped
the progression of this.

Because they were concerned if
it was dug into it may collapse.

SHATNER:
Are Pachacuti's mummified remains, and with them,

the secrets of Machu Picchu,
concealed in this chamber?

For now, the answers may lie
sealed behind a stone wall.

But perhaps there's another way

to solve the mysteries
of Machu Picchu.

Although the Inca did not leave
behind any written records,

they did encode information
in strange threads

that are known as quipus.

HYLAND: Quipus are twisted chords
that redefine what writing is,

because some of them are
incredibly complex

with hundreds of pendants,
dozens of colors,

and they have knots
that represented words,

and they were read
syllable by syllable.

If you're in an empire
like the Incas,

where people spoke many, many,
many different languages,

if you have a writing system
or a communication system

that is not tied to speech

but uses symbols, uses ideas,

then people who speak
different languages

can come together
and understand those records.

And what's really mysterious

is that there were
narrative quipus.

And, supposedly,
these narrative quipus

had biographies.
They had poems.

They had histories.
They served as letters.

The Incas would have used quipus

during the construction
of Machu Picchu.

If we could decipher them,

quipus could give us insights
into that whole process.

That could really unlock the
mysteries of the Incas for us.

SHATNER: Will translating
these intricate rope knots reveal

why the Inca built the mountain
kingdom of Machu Picchu?

It's an intriguing possibility,
and one that illuminates

how important it is to
decipher the relics of the past.

Like in the case of a
delicately crafted miniature

found hidden
in the jungles of Colombia.

It's a piece of art that
many believe tells the story

of an ancient culture
with riches so vast

they built a city
constructed entirely of gold.

Its name?

El Dorado.

SHATNER:
Spanish conquistadors, led by Francisco Pizarro,

capture the Incan
Emperor Atahualpa,

and kill 5,000 of his men
in the course of just one hour.

Pizarro is on a quest
to both conquer the New World

and plunder as much gold
as he can find.

Pizarro starts to take these
gold and riches

from the kingdoms of the Andes.

And this really starts
a precedent for conquistadors

trying to take riches
and send them back to Europe.

This quest for gold
is what drives them.

BELLINGER:
From the European point of view, once there was

the hint of gold up in the hills
of South America,

it was an absolute frenzy.

The indigenous people
all around them

were literally draped in gold,

the likes of which Europeans
never would see back at home.

SHATNER: As the Spanish conquistadors
encountered indigenous people

throughout South America,

they heard stories of a vast
city made entirely out of gold.

In fact, the Spanish came up
with a name for the golden city.

They called it El Dorado.

The name El Dorado comes from
the words "the golden."

That's literally
what it translates to.

The Spanish trekked through
rain forests

and across swollen rivers
and up icy mountains

in search of what they assumed
had to be a hidden city of gold,

a place of untold riches
just waiting to be plundered.

There were similarities
to all of these stories,

and that kept
the Spaniards thinking,

"Well, maybe there's something
to this. Maybe it's not a myth."

And because they don't know
exactly where it is

it starts to be thought of
as a lost city.

SHATNER:
The Spanish belief that El Dorado

was a real lost city of gold
was reinforced

when they came into contact
with a mysterious civilization

known as the Muisca people.

The Muisca were the indigenous
people who occupied

this particular
highland area of the Andes,

which is, today, Colombia.

And they occupied this area
for about a thousand years,

beginning in 600 AD.
And, in fact,

they were so sophisticated

that they really
take their place alongside

better known empires
in the region, such as the Inca.

LEVY:
The Muisca were incredible goldsmiths.

They were really skilled
craftsmen at goldwork-

finely wrought,
thinly pounded gold.

They made animals,
they made gold

that was depictions
of their deities.

SHATNER:
Spanish Conquistadors searching for El Dorado

came to believe that
it was built by the Muisca

because of a curious ritual
they supposedly performed

high in the mountains

at a body of water
known as Lake Guatavita.

When the Muisca
initiated a new leader,

there was
a very specific ceremony

that they performed
on Lake Guatavita.

The leader would
plaster his body in gold dust.

He would climb into a raft
surrounded by priests.

At his feet
was a pile of offerings,

gold and jewels.

Once they had paddled out
to the middle of the lake,

he would make his offering
to the god.

And that involved dropping
all of the valuables

off the raft into the water,

and then diving in himself,
so that the gold dust

would be washed from his body.

LEVY: When the conquistadors
begin to hear about these rituals

that involve gold
and a golden man,

it stood to reason that
this place, El Dorado,

a lost city, is going to be
somewhere out there.

SHATNER:
The Spanish heard rumors that the Muisca

had performed this golden
ceremony at Lake Guatavita

for a thousand years,

since the beginning
of their civilization.

The conquistadors
believed that El Dorado

must be an ancient, hidden city
where, centuries earlier,

the ancestors of the Muisca
had stockpiled

vast amounts of gold
to be used in the sacred ritual.

LEVY:
As conquistadores kept trying to find El Dorado,

they found a lot of gold,

they found goldwork
made by the Muisca

that was really, really
elaborate,

and they kept getting
just enough

to sort of tantalize them
to know or believe

that there would be more,

but they never quite found

the El Dorado
that they had been looking for.

SHATNER: Although the Spanish failed
in their quest to find El Dorado,

for centuries, treasure hunters
from around the world

journeyed to South America
in search of the lost city.

And then, in 1912,

an incredible discovery was made

at the bottom of Lake Guatavita.

LEVY: Hartley Knowles, a British
engineer, came to Lake Guatavita

and, with a mining company,
was able

to completely drain the lake
to the bottom.

He found gold, rumored
to be about $20,000 worth,

but what happened was
as the lake went down,

all the silt and mud
at the bottom

hardened in the sun
until it was like concrete,

and they couldn't get
any more gold out of the bottom.

JAGO COOPER:
They cut a notch out of the side of the hill

and drained the lake.

But it only remained drained
for about 24 hours

before the lake refilled.

But what they found was some
objects that sort of showed that

this idea of offerings being
thrown into the lake was true.

SHATNER: Even more incredible
evidence of the Muisca rituals

was found later,
in 1969, in a nearby cave.

BELLINGER:
In 1969, some villagers

stumbled upon an absolutely
spectacular find

in a ceramic jar.

They found an exquisite raft

crafted all out of gold.

The workmanship was incredible.

But even more exciting is that

it corroborated everything
that had been written down

about the Muisca rituals
in Lake Guatavita

when they were
initiating a new ruler.

SHATNER: Since the story of the
ritual performed by the Muisca chief

was proven to be true,
does that suggest that

the tales of El Dorado,
the lost city of gold,

could also be true?

And if so,
where might it be hidden?

LEVY: Cities in the Amazonian
region, over time, have a tendency

to become absorbed
and enveloped by the jungle.

South America is an incredible
place to keep secrets

and for a lost city
like El Dorado to dwell.

SHATNER: Could El Dorado have
really existed only to be swallowed up

by the dense jungle, its vast
riches buried and beyond reach?

Perhaps one day other precious
artifacts like the golden raft

will be unearthed and provide
yet another clue

to solving the mystery
of the lost city of gold.

But there's another
object of fascination,

this one made of stone,

that inspired a search
of an entirely different kind-

a quest to find
a mythical outpost

of the infamous Nordic warriors

known as the Vikings.

SHATNER:
According to a collection of medieval prose

called the Icelandic Sagas,

a group of Vikings were said
to have taken a daring voyage

from Scandinavia
across the Atlantic Ocean

on a journey to reach a
faraway realm known as Vinland.

The Sagas describe Vinland
as a bountiful paradise

and, for centuries,
historians thought

it was merely the stuff
of myth and legend.

But then, in 1960,

Norwegian husband-and-wife team
Helge and Anne Ingstad

set out to prove not only
that Vinland was a real place

but also that it was located
in North America.

SCOTT A. MELLOR:
Helge and Anne Stine Ingstad combed the entire

coast of Canada
to try and find this site.

And they were very confident
that the Sagas

had an element of fact about it.

And they were right, they did.

SHATNER:
The Norwegian couple uncovered the remains

of a Viking settlement on the
northern tip of Newfoundland

that dated to
the 11th century AD.

This profound discovery,
which is now

a UNESCO World Heritage Site
called L'Anse aux Meadows,

is indisputable proof that
the Sagas may hold more truth

about the Vikings
than we ever thought possible.

BILL: L'Anse aux Meadows
is actually the physical evidence

of Scandinavian habitation
on the North American continent.

The Vikings
did discover North America

500 years before
Christopher Columbus.

THOMPSON: We know that there were
Viking settlements in the New World.

When I was a young boy
that was considered a legend.

Now it is historical fact.

And they may have actually been
more extensive

than we see
in the Sagas themselves.

MELLOR:
L'Anse aux Meadows is in Newfoundland.

And we know that
they were there.

But then, of course,
it begs the question,

how far in did they get?

SHATNER:
Is it possible the Vikings

traveled deep
into North America?

Well, there are those
who believe the answer is yes,

and they claim
the proof can be found

more than 2,000 miles away
from Newfoundland...

...in Alexandria, Minnesota.

This small city, about 130
miles northeast of Minneapolis,

is home to the Runestone Museum.

Inside is an artifact that
many point to as evidence

that the Vikings traveled
well beyond

the northeastern tip of Canada

and into the heartland
of America.

Because on display is the
remarkable yet controversial

Kensington Runestone.

The Kensington Runestone is
about the size of a gravestone.

And it was discovered
in 1898 in Kensington

in Douglas County in Minnesota

by a Swedish immigrant,
Olof Ohman,

and it is covered in runes.

And what intrigues people
is that

it seems to be
incontrovertible proof

that the Vikings were there.

THOMPSON:
Runes are Viking works of art.

And runestones are located

pretty much throughout
the Viking realm.

Runes were kind of cumbersome
to write with.

And so things
tended to be short.

So what you end up with
is very often cryptic poetry

with a tremendous
amount of meaning

packed into
very obscure passages.

So, even to be able
to understand these runes

was sort of a master craft.

SHATNER: For over a century, people
have speculated about the meaning

of the cryptic markings
on the Kensington Runestone.

By comparing it with other
known runestones,

historians have theorized
that the stone

tells the tale
of a Viking expedition.

McMAHON:
Allegedly, the Kensington Runestone

has an intriguing story

written in Runic script,

about a group of about 30
Vikings

who journey from Vinland

all the way down
into what is now Minnesota.

Now, ten of them are massacred

en route by the local people.

But the suggestion
is that these Vikings

made it to the interior
of North America.

SHATNER:
Based on this translation,

many believe that the Kensington
Runestone is a memorial

to Vikings who died on their
quest to explore North America.

But skeptics have questioned
the stone's authenticity.

McMAHON:
This could either be a genuine account

of an incredible journey
by intrepid warriors

deep into America,
or the other theory

is that this was
Swedish immigrants

trying to prove
to their neighbors

that they had
a much longer presence

and an entitlement to be there

because their ancestors
had been there.

But the idea that these warriors
ventured deep into North America

into places that
we know well today, Minnesota-

that really
captures the imagination.

Did a group of Viking explorers,

adorned with axes and shields,

venture deeper into
the forests of North America

than we've been
led to believe?

Whatever the truth may be,

discoveries that rewrite
the timeline of human history

have far-reaching implications.

Such is the case with an ancient
kingdom in Southeast Asia

that constructed what may be

the oldest pyramid on Earth.

In the countryside
of this lush, tropical island

located in the Indian Ocean

lies a mountain that,
from a distance,

looks no different from
any other peak in the region.

But close examination
of the mountaintop reveals

a series of ancient
stone terraces

that are littered with thousands
of megalithic blocks.

This intriguing site is known

as Gunung Padang.

NEWMAN:
Gunung Padang has all these

remarkable kind of hexagonal
basalt columns

as part of
the entire construction.

Hundreds of thousands
of them, in fact.

Each of the stones-
they weigh up to

about a third of a ton each.

They make up the foundation,
and they're also placed

in certain configurations
at the top.

There's something very powerful
about this place.

It was only really
rediscovered by farmers

over the last few decades.

It is almost untouched.

It's like it hasn't been known
about for thousands of years.

It makes you wonder who
could have done this and when.

SHATNER: The thousands of stone
blocks strewn atop Gunung Padang

are a perplexing sight.
It's hard to imagine

what structure
they could have been part of

or what purpose they served.

And the origin
of these curious ruins

has long been
shrouded in mystery.

But in 2013, archaeologists
excavating the mountain

discovered that the truth
about this mysterious site

is hidden beneath
layers of dirt and rubble.

COLLINS:
A team of experts did drilling,

they did radar surveys and
they did radiocarbon testing.

And what this revealed
is that, beneath the site

that is visible today,
which includes a number

of incredible stone settings
and rock mounts,

is something
even more incredible.

We now know that this site

does actually conceal beneath it

a massive pyramid complex.

NEWMAN:
Gunung Padang is really like a step pyramid

buried under stone and earth.

And the evidence suggests
this is extremely ancient

and is a very,
very important place.

SHATNER:
The revelation that Gunung Padang is actually

the ruins of a massive pyramid
made headlines around the world.

And in recent years, further
investigation of the site

has been led
by geologist Danny Hilman.

Danny and his team believe
they have uncovered evidence

of a hidden chamber.

SHATNER:
The discovery of a chamber buried underground

has added to the mystery
of Gunung Padang.

But the most significant
revelation so far is that

this structure might be
the oldest pyramid ever built.

SHATNER:
Ancient Egypt's Pyramid of Djoser

has long been considered
the world's oldest pyramid.

But based on
Danny Hilman's research,

Gunung Padang's buried pyramid

could be ten or even
20,000 years older.

If Gunung Padang
is a 20,000-year-old pyramid,

it would place an hitherto
undiscovered culture

at the heart of Indonesia.

And it would completely disrupt
our understanding

of the evolution of human
technology around the world.

SHATNER:
Do the technological achievements

of a lost civilization
lie hidden

within the stone chambers
of this ancient pyramid?

It's no surprise that
the empires of the past would

go to great lengths to conceal
their most precious secrets.

Such is the case surrounding
the actual resting place

of one of the most
feared rulers in history.

It is the mystery
of the lost tomb

of Genghis Khan.

SHATNER:
Towering above the sparse landscape is a massive,

130-foot-tall statue
made of stainless steel.

This magnificent monument
is a depiction

of Mongolia's most famous ruler:

Genghis Khan.

THOMPSON:
Genghis Khan is one of the most prominent figures

in all of history.
And he came up as

a very small, minor player
in what was a small,

minor country that most
of the world hadn't heard of.

But by the time he had died,

he had conquered
most of the known world.

STEAVU:
Genghis Khan is unquestionably

Mongolia's greatest cultural

and historical
and national hero.

He was at the head of

one of the largest empires
in the world,

second only
to the British Empire.

And many people,
maybe outside of Mongolia,

might remember Genghis Khan
for the bloodshed and conquests.

But he was also at the origins
of many technological,

scientific, astronomical
developments and advancements.

SHATNER:
After 20 years of empire building,

Genghis Khan died
in the year 1227 AD

while battling
the Western Xia dynasty.

Khan's exact cause of death
is a mystery.

But before he passed,
he commanded that

his final resting place
should be unmarked

so that his tomb
would be undisturbed forever.

STEAVU: The circumstances
of his burial are quite mysterious.

According to legend,
Genghis Khan's body

was brought back to Mongolia

by a group of 2,000 servants

who were guarded
by a group of soldiers.

The servants were all killed
by the soldiers.

Now, the soldiers themselves
were then killed

by a second group of soldiers

who then themselves
committed suicide

so that the burial site
would remain

forever undisturbed and unknown.

THOMPSON:
Many great rulers in many parts of the world

have wanted not to display one's
body, but rather to hide it.

And that would have been
the practice by Genghis Khan.

Because he knew that his tomb,
if it was ever uncovered,

would be an enormously political
tool for whoever uncovered it.

And he wanted
to control that legacy.

SHATNER: In the eight centuries
since Genghis Khan's death,

many have tried
to find his tomb.

But thus far, no one
has been able to defeat

Khan's drastic measures
to keep its location a secret.

Which naturally begs the
question: where could it be?

A French archaeological
expedition ventures

deep into this rugged region
of northern Mongolia

to find Genghis Khan's
lost tomb.

The team believes that
the tomb may be hidden near

a particular mountain peak that
is known is Burkhan Khaldun.

SHATNER:
Burkhan Khaldun is almost 8,000 feet high

and covers more than
93 square miles.

Exploring this vast,
rugged terrain is made

even more difficult
because in 2015

the mountain was designated
a UNESCO World Heritage Site,

rendering if off-limits
to any excavations

in search
of Genghis Khan's tomb.

Mongolians, in general,
still desire

to honor Genghis' Kahn's wishes.

They discourage archaeological
digs to try to find the tomb.

He is still very, very much
a hero in Mongolia.

And his wishes
are still respected.

SHATNER:
Because of the restrictions against

searching Burkhan Khaldun,

members of the French
expedition decided that

the key to finding
Genghis Khan's tomb

was to explore the mountain
from the sky.

And in 2016, they used drones

equipped with both photographic
and infrared cameras

to do an unprecedented survey
of the area.

SHATNER:
After surveying the mountain from above,

the French team
made an extraordinary discovery.

They identified a mound
that was 130 feet high

and 820 feet wide

that they believe
might be man-made.

The French team
that accessed the mountain

identified that
the pyramid-shaped elevation

also had a little shrine

and it sits atop
of this sacred mountain.

So, they speculate
that this would

probably be where
Genghis Khan is buried.

SHATNER:
Is it possible that the structure

discovered by the French
expedition on Burkhan Khaldun

is the tomb of Genghis Khan?

For now, that question
is unanswered,

because the Mongolian people
remain committed to honoring

the revered emperor's dying wish

that his tomb
should never be found.

SHATNER:
Located near the border of Russia and Mongolia,

this region is known
for its vast grasslands.

But in 2021, archaeologists from
the Russian Academy of Sciences

made a remarkable discovery.

While conducting
an aerial survey,

they spotted an enormous symbol
known as a geoglyph

that was formed using carefully
arranged pebbles and sandstones.

PAUL BAHN:
In Central Asia we have something called

the Siberian Bull.

It's a very simple drawing
just done with dark stones

making the outline of a tail
and the back legs of an animal.

And, fortunately,
it's linked quite closely

to an early Bronze Age burial,

so we reckon it must
date to back to 2,000 BCE.

It is some 4,000 years old,
and still there.

Research on this
is still ongoing,

but it shows that
there's still so much

about these geoglyphs
and the beliefs and the values

that were held by
the ancient people who made them

that we do not know.

SHATNER: The Siberian Bull is
ten feet tall and 13 feet long,

and is the first geoglyph
of an animal

discovered in Central Asia.

But what's
more remarkable is that

even larger ancient geoglyphs
have been found

all over the world.

Many of them are so vast

that they can only be identified
from the sky.

BAHN:
Geoglyphs are an astonishing phenomenon.

They're found in many,
many parts of the world,

primarily in deserts.

And they are often of huge size,

involving an enormous
amount of work.

Geoglyphs can be divided up,
really, into the ones

that just look like
geometric shapes to us,

and there are
many, many of those.

You have lines which just
look like roads or paths

going on for miles.

And then, of course, you have
what seem to us to be

depictions of birds,
animals, humans.

And they must all have
very different meanings

to the cultures
that produced them.

NEWMAN:
In March 2022, archeological researchers found

what could be the largest
geoglyphs on the planet

in the Thar Desert
of ancient India.

They stretch over
a huge distance,

and one of them kind of
forms into what appears to be

a kind of strange spiral.

And there's other ones which
are like sinuous serpents.

MIANO:
One of the more fascinating geoglyphs

is the Uffington White Horse
that was found

in Oxfordshire, England.

They dug trenches
and they filled them with chalk

to create this beautiful horse,

which itself is 3,000 years old.

And we expect to find more
as time goes on.

SHATNER:
Why did so many ancient cultures across the world

labor to carve these
enormous figures and symbols

that could only be fully seen
from the sky?

Well, according
to some researchers,

it could be because the people
who created the geoglyphs

intended them to be viewed
not by man but by gods.

BAHN:
It seems a reasonable supposition

that a lot of these images,
which only make sense

from the air, were very much
tied to things in the heavens.

There are astronomical
orientations

of some of the lines

and some figures may
represent constellations.

But there are so many
possibilities because there are

so many hundreds
of different geoglyph types

that you can't simply put
one explanation on all of them.

SHATNER: Recently, a new theory
has been proposed to explain the famous

Nazca Lines in Peru, which date
back more than 2,000 years.

BAHN: The great Nazca Lines
are done in one continuous line-

the monkey or the spider.

We've always assumed that the
people who made the Nazca Lines

were trying to communicate
with gods, ancestors,

spirits or whatever.

But there was an idea
put forward quite recently

by an American scholar

who thought that
some of the geoglyphs

might be linked to runoff from
hills and channeling the water

and helping the crops to grow.

MIKE TUCKER: There's a trend in
backyard gardening called permaculture,

where the gardener
digs trenches and

creates swells or hills
to sequester the water

or capture the rainfall,

so that way the ecosystem
supports their own garden

and they don't have to bring in
extra irrigation.

MICHAEL WYSESSION:
In places like where the Nazca Lines are,

we see a very barren,
arid, dry place, currently.

But if you went back
thousands of years,

you'd find alternating periods

of extreme rainfall events.

NEWMAN: We don't have written
records of what they were thinking

or what they were doing and why
they were building these sites.

The fact is there are
different theories

in different
parts of the world as to

what they could have
been created for.

But whether it's in a desert

or whether it's like chalk hill
figures in ancient Britain,

at least they still exist

and we can appreciate
and study them today.

From high in the Andes mountains
to the steppes of Mongolia,

the evidence of powerful
bygone civilizations

is all around us.

What can we learn from the ruins

of these once-great cultures?

Perhaps they show us
a cautionary tale

of how empires rise and fall,

as well as reshape
our understanding

of human history as we know it.

It's clear that our innate need
to explore the mysteries

of our ancient past
will keep the search going,

because the most closely
guarded secrets

of these
mighty kingdoms remain...

unexplained.

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