Original subtitles

Tonight... They've been called

the world's greatest archeological enigma.

AARON HINKLEY: Everyone focuses on the Nazca Lines

because of just how mysterious they are.

LAURENCE: 2,000 year-old drawings so massive,

they can only be seen from the air.

But what are they and why were they created?

FORREST BURGESS: We know they didn't just appear

out of thin air, but there is virtually

no historical record of previous societies in Peru.

Now, we examine the top theories behind their mysterious origins.

Maybe the Lines were ritual battlefields,

but I don't think that's all they ever were.

They found a collection of severed heads,

and this really suggests that the Nazca Lines

could be connected to ritual human sacrifice.

This is why we think the Nazca Lines

may have been repurposed.

LAURENCE: Can new research finally unravel their secrets?

Researchers make a shocking discovery

and, if this theory is correct,

they might have solved one

of archeology's greatest riddles.

What is the true purpose of the Nazca Lines?

♪ ♪

♪ ♪

LAURENCE: September, 1926. Nazca, Peru.

Archeologist Toribio Mejia Xesspe

leads an expedition in the Peruvian desert.

Xesspe and his team have been drawn here by a discovery

of a giant underground acropolis full of hundreds of mummies.

When most people think of mummies,

they tend to think of Egyptian mummies,

but, in fact, the oldest mummies in the world

are from Northern Chile and Southern Peru.

LAURENCE: Dating back over 7,000 years,

they're known as the Chinchorro mummies.

Xesspe examines some that are wrapped in thick layers

of expertly-woven cotton textiles,

covered in vibrant images of mystical figures and animals.

LAURENCE: One day, while taking a break

from his work, Xesspe hikes up a nearby hill.

He gets to the summit, looks out over the desert plain,

and he's met with a stunning sight

he can barely believe.

Xesspe sees a series of thick lines

carved into the rocky desert.

Some stretch as far as his eyes can see.

These lines are incredibly long, perhaps miles,

and they're straight as a ruler.

At first, he thinks they're trails or roads,

but he notices that several of them plow right

over the mountains and other rugged terrain.

Not exactly what you would do if you were building a road.

Eventually, he realizes a lot of these are forming

geometric shapes, you know, kind of standard rectangles, spirals,

squares, triangles,

some of them as big as a football field,

to put it in perspective.

LAURENCE: Intrigued, Xesspe puts his mummy research

on hold to investigate.

One of the things Xesspe realizes would be useful is

to get a better look at these from higher up.

So he calls in the Peruvian Air Force

to get that overall aerial view.

They can fly over it, see what's really going on.

When they reach altitude,

the pilots can't believe their eyes.

The lines and shapes cover an area

that stretches for hundreds of square miles,

far beyond what Xesspe originally saw.

There are spirals, zigzags...

There are drawings of birds, spiders, monkeys,

immense in scale.

These images are impossible to see

in their entirety from the ground,

so the pilots realize they're probably the first people

to ever truly witness the scale of this unusual formation.

LAURENCE: The strange markings become known as the Nazca Lines.

When you look at how many Lines are actually there,

it's an incredible number.

Over 800 Lines total, hundreds of geometric shapes

and at least 100 animals are present in this area.

Some of the Lines are thousands of meters,

all the way up to 25 miles, and this is quite incredible.

The precision of these Lines is super impressive,

even by modern survey standards,

because many of them are just dead straight.

FORREST BURGESS: And for 100 years now,

ever since Xesspe first spotted them,

they've been a mystery.

Who made them? When were they made?

Why? What's the purpose of them?

LAURENCE: Initially, it's believed

the Inca are responsible.

Beginning in the 12th century, the Incan Empire

eventually rules a large area of South America

until Spain conquers them in the 1530s.

But scientists eventually date the Lines to between 300 BC

and 800 AD, which means all of them

predate the Incas.

LAURENCE: In fact, some of the Lines

are almost 2,500 years old.

We know they didn't just appear out of thin air,

but there is virtually no historical record

of previous societies in Peru because the Incas,

and later the Spanish, made it a policy to suppress

and destroy every trace of the cultures they conquered.

And so who built them remains one of the biggest mysteries.

LAURENCE: But how they were made is much easier to answer.

The ground is covered with a desert varnish.

It's these small pebbles, rocks that have

this black patina on them.

When you scrape away this darker layer,

you reveal a lighter layer underneath.

It's a stark contrast, like a negative image.

So that's the method they used.

LAURENCE: The region is also one of the driest on Earth.

It receives only a millimeter of rain a year,

and because there's no rain in this area,

these Lines were able to survive for thousands of years.

LAURENCE: After 13 years researching the Lines,

Xesspe presents his findings at a conference in 1939.

This conference is the first time that people

from outside of Peru have heard of these Lines.

Xesspe's work has been mostly cataloging and measuring them.

He doesn't suggest an overarching purpose

for the Lines, but it gets a lot of people excited.

LAURENCE: Among those intrigued, a scholar named Paul Kosok.

Kosok is a history professor from Long Island University

in Brooklyn, and he's in Peru studying pre-Columbian society

and culture, particularly focused

on their irrigation systems.

LAURENCE: Inspired by Xesspe's work,

Kosok travels to Nazca to try and solve the puzzle.

FORREST: In June of 1941, he's charting several

of the shapes in the vast desert plain.

As he contemplates their purpose, he glances up

at the setting sun and is struck with a sudden epiphany.

Kozok realizes that the Line he's charting

points directly at the sunset over the horizon.

LAURENCE: Kosok has a revelation about what these lines could be.

It's late June in Peru, just about the time

of the winter solstice in the Southern Hemisphere.

It strikes him that these lines could be

an astronomical calendar.

♪ ♪

Kosok returns to Lima with this incredible story

of discovering what might be the largest astronomy textbook

in the world, etched into the sands of the desert.

LAURENCE: There, Kosok consults with a German mathematician

named Maria Reiche, to figure out

more specifically what the calendar is tracking.

So Reiche works at the National Museum of Lima

and is a restorer, and she hears about this and really

gets interested in exploring in much more detail

how these figures could work

from an astronomical perspective.

LAURENCE: On her first trip to Nazca in 1941,

Reiche identifies 16 lines

that point directly at the rising

or setting sun on the dates of the solstice.

Reiche also thinks she knows why the Lines' creators

might have made this calendar to begin with.

One of the things Reiche did really well

was track a large number of correlations

between the different figures and different elements

of astronomical importance.

Two examples are a line on the spider figure that points

to Orion and a set of lines

on another figure that point to the Pleiades.

Many ancient civilizations are based

around agriculture and farming,

and knowing when to plant or when to harvest

is vitally important.

Often, these times would coincide

with atmospheric patterns, like rain.

AARON: But what do you do in a place where it never rains?

FORREST: Most of this region's water comes from periodic runoff

from the surrounding mountains.

So a farming culture with an environment

with virtually no rainfall would rely heavily

on a celestial calendar to determine planting times

for their survival.

When that water comes,

you need to be ready.

MICHAEL DENNIN: So one constellation you can use

in this fashion is the Pleiades.

When they show up in November, you know you're really close

to the rainfall up in the mountains.

You're about to get your runoff,

so you start your planting season,

and when the Pleiades leave the sky later in the year,

that's when you know it's time to start your harvest.

LAURENCE: Reiche reports her findings to the press,

providing the first published theory on the Nazca Lines.

AARON: To this day, Reiche's interpretation

of the Lines dominates the public's perception of them.

She's dubbed the Lady of the Lines.

FORREST: There's plenty of reason to believe this theory,

because there are examples

of many other prehistoric cultures

of earthworks being constructed to aid

in astronomical sightings and calendars.

LAURENCE: The famed Stonehenge may be one such example.

FORREST: In the 1960s,

an astronomer named Gerald Hawkins

calculated the positions of its standing stones

using an early IBM computer and announced that the monument

was designed to predict astronomical events.

His work was a sensation around the world,

and inspired a new branch of science,

known as archeoastronomy.

LAURENCE: In 1968, Hawkins visits Nazca to study the Lines,

using the same computer matching technique.

MICHAEL: In particular, what Hawkins looks at

is 21 triangles and 70 or so lines,

and really asks, "Okay, how well correlated

are these with astronomical phenomena?

His conclusion? The connections Reiche found

were only coincidental.

One of the issues is that there are just

so many of the Lines and in such a large variety

and in so many directions, that, to suggest all of them,

or even most of them, are connected to astronomy

is a clear stretch.

MICHAEL: Reiche and Kosok, when they see the findings,

they don't disagree with them.

I mean, the computer findings are pretty solid,

but they do point out

that this isn't necessarily conclusive.

It doesn't rule out that some of the Lines

aren't astronomical.

FORREST: They believe there are some alignments, which are done

on purpose to be used as a celestial calendar,

but there must also be a much larger and grand purpose

to the design that they haven't figured out yet.

LAURENCE: When Peruvian archeologist

Toribio Xesspe discovers the Nazca Lines in 1926,

the first thing that strikes him is their incredible scale.

MICHAEL: When you look at these shapes and features,

they're so huge, they can only be viewed

from above and very high in the sky.

So this does mean that the culture that built them

would actually never be able to see them directly.

FORREST: We know there weren't planes or other flying vessels

2,500 years ago, when the Lines were first created,

but somehow these people decided to craft designs

meant to be seen from what, to them,

would have been an impossible viewpoint.

It doesn't make sense.

LAURENCE: Unless the Lines were designed for another purpose.

In 1968, Swiss author Eric Von Daniken

claims he knows the reason.

The Lines aren't built for anyone on Earth.

Instead, they're built as a landing guide

to an extraterrestrial species

that once visited the Nazcans from the heavens.

♪ ♪

One of the first Europeans to see the Lines is

a magistrate named Luis de Monzon in 1586.

FORREST: He initially suspects that they are traces

of ancient roads, which, of course,

we know isn't true these days.

CAROLINE CORY: When he asks the locals about them,

he's told of a legend.

In very old times, the Nazcans were visited

by people they called the Viracochas.

They referred to as saintly persons.

The locals tell De Monzon that the paths

were actually built for them.

LAURENCE: Viracocha is also the name of a Nazcan god.

This deity dates back to around 3000 BC,

and the legend says that he came from the sky in a golden boat,

from the other side of the Milky Way,

to be specific.

In the oldest depictions, he's pictured

with a cone-shaped skull and only four digits

on his hands and feet.

LAURENCE: Von Daniken believes these legends are a reference

to extraterrestrials.

MICHAEL: One of Von Daniken's key thesis and beliefs

is that the ancient people saw these extraterrestrials,

these aliens, as gods.

FORREST: Von Daniken believes that when the Viracochas,

or aliens, first visit,

they teach the Nazca people how to make these Lines.

FORREST: The earliest Lines are built as a landing pad

or navigational marker,

basically an airstrip for these alien ships.

We don't know if these aliens ever made any return visits,

but Von Daniken believes that eventually they stop coming,

and the Nazca decide to get creative.

FORREST: They want the Viracochas

to return back as soon as possible,

so they start building more and more elaborate Nazca Lines.

LAURENCE: Von Daniken's 1968 book,

"Chariots of the Gods," turns the Nazca Lines

into an international phenomenon.

MICHAEL: When Von Daniken first came out with his book,

this really generated a lot of interest,

a lot of excitement, a lot of buzz.

It was a very, very intriguing idea

that maybe aliens had visited.

FORREST: And, in fact, some people look

at one of the Nazca geoglyphs in particular, and believe

it may prove Von Daniken's theory.

LAURENCE: Known as The Astronaut,

this figure covers nearly 100ft of a hillside,

overlooking the desert.

Some call it The Astronaut because it looks like

it's wearing a space helmet,

which, of course, is a modern interpretation.

Most historians refer to him as the Owl Man.

AARON: It's a humanoid figure, but clearly not entirely human.

It features large, round eyes, and it seems to be

waving hello to someone in the skies.

CAROLINE: A thousand years after the creation

of the Nazca Astronaut, the Inca build a statue

of Viracocha in Cusco, raising his right hand,

much like The Astronaut.

Scholars believe the Nazca Astronaut

could be an image of the same god.

AARON: We don't currently have any way to know

if the Nazca Astronaut is an alien.

There are no records from this society,

apart from the Nazca Lines themselves.

LAURENCE: But one ancient practice

might offer more insight.

FORREST: Remember those ancient Peruvian mummies

Xesspe was examining?

Well, shockingly, many of them have elongated skulls.

Today, it might be seen

as a strange and disturbing look,

but it's believed that the natives did this on purpose,

by attaching wooden boards to their infants' heads.

Several mummies are even found

with these boards still attached.

LAURENCE: The question is, why?

We've seen Viracocha represented with an elongated head,

and many representations of aliens

with a similar head shape.

Well, perhaps they're trying to emulate the appearance

of their gods, who had similar features.

LAURENCE: A 2017 discovery takes this claim a step further.

FORREST: Dr. Konstantin Korotkov,

professor of biophysics

at St. Petersburg Federal University,

shows the press these mummies

that he believes aren't human at all.

They look like they're covered in plaster,

but Korotkov explains,

"This is just calcification and protective material."

They have elongated heads, large round eyes,

and just three digits on their hands and feet.

He calls it, quote, "Another creature,"

different from anything else in our fossil record.

These mummies are made famous by a web series

claiming to investigate their authenticity.

Millions of people watch as stupefied scientists

declare them to be the genuine article.

The body they examine is indeed organic,

and it dates back 1,700 years.

LAURENCE: But when another team of scientists

inspects the mummies, they're proven to be fake.

MICHELE KOONS: They discovered that these were mummies

that were modified for this hoax

and really turns out to be quite disturbing.

FORREST: These bodies are made from real indigenous mummies,

which have been mutilated to make them look like aliens.

Their ears and noses are sliced away

and the alterations are covered up

with a white plastery powder.

But the other mummies with the elongated heads

remain genuine.

Those are humans who most definitely

gave themselves an otherworldly appearance.

Why? We don't know.

AARON: I think everyone would like to know the answer

to that question.

Maybe they were trying to connect with another culture

that once visited them from above.

Or maybe they just heard stories of some visit

from long ago and were inspired.

LAURENCE: Nazca, Peru, is home

to two incredible ancient phenomena,

the Nazca Lines and a necropolis

of South American mummies, several thousand years old.

FORREST:veryone focuses on the Nazca Lines

because of just how massive and perplexing they are.

But we can't lose sight of the mummies,

because the two may be intricately linked.

AARON: Mummification here dates back 7,000 years.

That's a full 2,000 years

before the first Egyptian mummies.

MICHELE: In Egypt, they used different techniques

to dry out the body before they would wrap it.

In this region, they didn't do anything artificial.

The mummies were able to preserve

because this desert environment is so dry.

In fact, some of these mummies are way better preserved

than what we even see in ancient Egypt.

FORREST: Dry conditions are one part of the reason,

but the other is the technique they used.

While the Egyptians used fine linens, the Nazca mummies

are wrapped in very long, thick cotton and wool textiles,

which are embroidered with a skill and quality

that's unmatched by any other civilization.

LAURENCE: In 1983, Swiss historian Henri Stierlin

thinks he knows their secret.

FORREST: Stierlin is an art historian,

and he realizes what it would take for these ancient people

to craft these textiles.

They would need a lot of space and huge long looms,

essentially an ancient version of a factory,

to churn out this incredible amount of cloth.

He looks around at what they have nearby

and he determines the Nazca Lines

might be the place.

♪ ♪

LAURENCE: Stierlin writes a book

called "Nazca, the Key to the Mystery,"

which details his theory.

AARON: One of the most stunning discoveries

about these mummy wraps is that they are made

from a single piece of cotton thread,

which can be dozens of miles long.

This idea of a single thread is reflected in the way

the Nazca Lines are created too.

They're made with a single line,

which starts and ends in the same spot.

FORREST: So first they need to make very long threads.

Stierlin believes they use the wide clearings

within the geometric shapes as sacred spaces

for spinning the cotton fibers into these threads.

As the threads are made, Stierlin thinks the weavers

would lay them out along the Nazca Line's animal designs.

LAURENCE: According to Peruvian beliefs,

each animal carries a different significance.

FORREST: So, depending on who they're burying,

they would lay the thread in a different Nazca Line

to infuse it with the power of that family's chosen animal.

For instance, the whale provides success in fishing.

The hummingbird provides fertility.

LAURENCE: As far as the actual weaving, Stierlin thinks

this takes place within the Nazca Lines themselves.

So Stierlin had this idea that the Nazca Lines

acted as a giant loom,

because there are these posts within the Nazca Lines,

the people would take the thread and wind

back and forth over the Lines to create the textiles.

FORREST: There were posts found at the Nazca Lines.

That's actually how scientists are able to date them

in the first place.

They test the remains of organic wooden posts

discovered nearby.

Stierlin believes these posts could have been

the framework to support this giant loom system.

LAURENCE: Stierlin also finds a connection

in the drawings themselves.

MICHELE: So the designs on the mummy textiles

are very similar to what we see in the Nazca Lines,

a similar array of animals and plants.

FORREST: These ceremonial shapes might have been a part

of the entire process, from the weaving

through to the end of the mummification.

One single mummy shroud could have over

a million stitches on the main panel,

and another 800,000 or so on the borders.

This is a huge collaborative effort.

Making the mummies must have been a very sacred

and important process to these people.

So why not build a sacred and important

site to do it?

AARON: The Egyptian mummies were preserved

and wrapped by priests and elaborate rituals

inside impressive temples.

This could have been a prehistoric version

of the same thing.

LAURENCE: According to Stierlin's theory,

the operation may have expanded beyond the mummies.

♪ ♪

FORREST: The Nazca Lines mummy factory

may have eventually become a textile factory,

serving the entire Andean coast and parts of the highlands.

AARON: It's interesting because while you can't grow

many things in this environment, you can grow cotton.

It's one of the only useful crops they could have had.

FORREST: You have to wonder, how did they survive?

Well, if this was a place that could abundantly

manufacture cloth, they could have traded it.

MICHELE: But Stierlin's theory is really based off

of a lot of speculation.

There's no archeological evidence

that any weaving was done on these Lines.

He probably saw the posts and just had this idea

because textile production is so important in the Andes,

and textiles, in fact, were more important

than even some of the precious metals, like gold.

LAURENCE: But a new discovery in 1987

challenges Stierlin's theory.

About two miles away from the Nazca Lines,

up on a high plateau,

is a ceremonial center called Cahuachi.

An Italian archeologist named Giuseppe Orefici

has been in charge of excavations there since 1984.

He's working closely with an American archeologist,

Helaine Silverman.

FORREST: At Cahuachi, Silverman and Orefici have found

lots of chambers that we now believe to be workshops

for making textiles,

with remains of weaving materials found there.

When Silverman first publishes her work

in the "Journal of Field Archeology" in 1988,

she finds that Cahuachi is the center for the production

of these elaborate costumes worn by the Nazca priests

and where the rituals are performed.

In other words, Cahuachi is the mummy and textile factory,

not the Nazca Lines themselves.

LAURENCE: But some believe there's still a connection

between the two locations.

FORREST: The Nazca Lines might not have been

a mummy factory or textile factory,

but they could have been a place to reflect

while that process was happening nearby.

The entire area, both the Lines in the valley and Cahuachi,

perched above, was most likely a place of pilgrimage

for natives throughout the region,

a kind of religious tourism site

which included a funeral parlor and textile trading.

Visitors to Cahuachi would have had a fine view

of some of the Nazca Lines below,

and I don't think that's a coincidence.

♪ ♪

Many scholars have studied the Nazca Lines

and speculated about their mysterious designs,

but it's not until 2019 that a Japanese research team

takes a closer look at some of the animal patterns.

Their findings unlock a new possible theory

surrounding these shapes.

MICHAEL: The animals represented in the Nazca Lines

are referred to as biomorphs.

There's over 70 of these.

They represent a wide range of animals,

insects like spiders, monkeys, dogs,

and a wide range of birds.

FORREST: The animals range in size from about 50ft long

up to over 1,200ft, almost as tall

as the Empire State Building.

For about 100 years after these were first discovered,

no one really thought carefully about the animals.

They just classified them and noticed,

"Oh, there's animal biomorphs."

The reality is that these animals are shocking

because they don't exist in this area.

And so really asking the question, "Why these animals?

Why here?" Becomes critical.

LAURENCE: Researchers from Hokkaido University in Japan

attempt to answer these questions.

For the first time ever, these Japanese researchers

take a scientific approach to classifying

the species depicted in the Lines.

They want to identify precisely what species each drawing

depicts and where it comes from,

and then maybe they can find

some sort of logic or pattern to figure out the reason.

MICHAEL: So one of the exciting things is there's at least

18 species that they're able to identify.

There are a handful that they actually

just can't associate or identify a particular species for.

FORREST: Along with the rather obvious monkey

and llama, they identify a frigate bird,

a pelican, a guano bird, and even a killer whale.

The hummingbird, they identify it

as a hermit hummingbird, a species that lives

only in the tropics and subtropics,

far to the north and east.

The animals that the Japanese classify are all from places

with lots of water, like the coast or rainy jungle.

So, sure enough, they seem to be identifying a pattern,

and the team believes that water is the key to understanding

the purpose of the Lines.

LAURENCE: Throughout history, early civilizations

rely on an abundance of water to grow food,

but the dry desert conditions of the Nazca region

offer almost none.

FORREST: The very reason these Lines have survived

so long is because the area is so dry.

It only gets rain for maybe 20 minutes a year. 20 minutes.

So what do you do in a place where you don't get any rain,

yet you desperately need it?

For many ancient societies, you pray.

♪ ♪

The Nazca are a priestly society,

a deeply religious society.

We know this from the huge religious complex at Cahuachi,

which is like the Vatican for the Nazca people

and the whole coast of Peru.

The geoglyphs that surround it seem connected

to the complex and the rituals performed there.

And the Japanese team believes all of it is centered

around begging the gods for rain.

CAROLINE: The location of Cahuachi is not an accident.

There's actually a river that runs through the area

and across this stretch of desert,

the river runs underground.

It only emerges above ground again as it enters the lowlands,

right on the spot where Cahuachi's located.

This is where the water is given back to the people.

And so this is where they establish

their most important pilgrimage shrine.

LAURENCE: According to the Japanese team,

many of the Nazca Lines are arranged

in a path that leads directly to Cahuachi.

They're guiding the people to their sacred place

for water rituals.

All along that pilgrimage route, they would be saying

their prayers in the hopes that these mystical animals

swould bring along their region's rain.

Keep in mind, they're not actually praying for the rain

to fall in the desert, that won't help them.

They're praying for it to fall in the surrounding highland

and coastal areas, where they plant their fields.

CAROLINE: They're also praying for the rain

to come peacefully.

The climate along the Peruvian coast

can be unpredictable, and sometimes catastrophic,

with wild deluges that cause landslides and flooding,

wreaking havoc on the farmers.

So the whole belief system with this pilgrimage

along the Nazca Lines is centered around creating

a friendly, working relationship

with the gods who control the weather.

These gods are invoked and pleaded with

within the sacred spaces of Cahuachi and the biomorphs.

♪ ♪

LAURENCE: The team identifies the same species on rock art,

ceramics and textiles from the area.

ALEXEI VRANICH: They even made musical instruments

out of pottery.

FORREST: It must be quite an elaborate

and celebratory process.

You can imagine hundreds of people in colorful costumes,

performing ritual processions or dances along the Nazca Lines,

accompanied by drums and panpipes.

It's quite a spectacle.

♪ ♪

LAURENCE: There seems to be one more connection

between the Lines and water.

The last thing they find is that there are

several rock altars at the edges of some of the clearings,

right by the Nazca Lines,

and inside the altars there are crayfish claws,

crab skeletons, mollusk shells, the remains of sea creatures

here, in the desert, at 4,000 feet above sea level.

That's a bit surprising.

They're bringing these materials

from the largest body of water,

the ocean, as a way of asking the gods for water.

Once again, this supports the Japanese theory.

The Nazca Lines were a place for pilgrims to journey

from all around in the hopes of summoning

their most sacred resource.

LAURENCE: In 2019, Japanese scientists revealed

their belief that the Nazca Lines

were created as a prayer for rain,

a plea that unfortunately failed.

In the early fifth century,

this culture suffers their most extreme drought of all.

It's so bad that Cahuachi is abandoned.

There's no more sacred city for their rain and water rituals,

no place for a pilgrimage.

But after the drought, there are still artifacts

and human remains that suggest people

were still coming to the Nazca Lines.

So I think when you start to make theories

about the Nazca Lines and their purpose,

you have to split them into two distinct periods.

What were they used for before the drought

and what were they used for after?

I think before the drought,

the 2019 theory about the prayers

for rain is probably one of the best options.

That seems to check all the boxes.

LAURENCE: As for their use after the drought?

A scientist in the mid-1990s thinks he's figured it out.

MICHELE: So in 1996, David Johnson,

who is an American scientist,

traveled down to this region and he is the first

to really recognize these large,

almost well-like structures

in the desert, that we call puquios.

FORREST: The puquios are the spiral-shaped

stone staircases around a hole

that leads underground to stone-reinforced tunnels

under the earth, lined with waterproof clay.

MICHAEL: The locals really talk about these

as connected to an irrigation system,

a way of getting water to flow throughout the area.

One of the interesting things is how old they are.

They date back at least to the 6th century

and they're really connected with the ending

of this massive drought that decimated the area.

FORREST: Johnson realizes there's a connection

between the Nazca Lines and these puquios,

and starts working on a theory of his own.

He believes, after the drought, the Nazca people repurposed

their famous Lines and created a map for one

of the world's most sophisticated systems

of water management.

♪ ♪

LAURENCE: Johnson finds two underground water sources

in the Nazca desert to support his theory.

The first are rivers, which flow down

from the mountains before going underground through this region.

The second are geological fault lines that run

north to south that bring up their own water

from deeper beneath the water table.

When you look at this area,

not only is it one of the driest,

it's also one of the most seismically active areas,

and so there's actually a lot of fault lines in this region.

FORREST: Johnson notices lots of this area's ancient settlements

are located right next to faults and that there's

usually a puquio system there, in that spot, to tap

into its water source, and right on top of the faults,

in almost every case, he finds there are

Nazca Lines marking their paths.

The geometric shapes were designed to track and locate

underground water sources.

So, in this process, it's a way for the Nazca people

to take control of the water,

instead of just leaving it up to chance,

as to whether or not rain or runoff will show up.

These puquios ensure a reliable supply of water year-round,

meaning they're able to turn this arid desert

into arable farmland strictly through their own ingenuity.

LAURENCE: This method is not just relegated to antiquity.

Johnson is impressed the locals are

still using the system the Nazca created

some 1,500 years later.

There are around 30 of these puquios

still in use in the Nazca Valley.

But it really takes a lot of constant repair and work.

So many are falling apart and, you know, are out of use,

but they are still usable

where they've been taken care of.

LAURENCE: Johnson shares his insight

with archeologist Donald Proulx

and hydrologist Stephen Mabee.

FORREST: From 1996 to 2000,

they form the Nazca Lines Project,

plotting the course of several faults to look

for correlations with the Lines,

and they're able to confirm Johnson's ideas.

In almost every case they study, they find Nazca Lines

charting the path of the faults

and pointing to where the faults cross adjacent ridges.

As they finished it, they really came away feeling like they had

solved one of archeology's greatest mysteries.

If this theory is correct, the Nazcans have created a map

of the underground water sources,

which they can now tap into to survive.

It's like your local water utility map

on a one to one scale.

This is a complex but effective way of recording

knowledge onto the earth for later generations to use.

LAURENCE: But what about the animal shapes?

CAROLINE: This is why we think the Nazca Lines

may have been repurposed.

The animal shapes began as symbolic prayers

or offerings to bring rainfall.

LAURENCE: According to Johnson, they eventually become part

of the system as well.

While the most important mapping of the irrigation system

is done with geometric shapes,

Johnson writes that the animal figures

might have been used to name the different water sources

or indicate where they change direction.

CAROLINE: These puquios are an incredible achievement,

and the Nazca Lines are a huge part

of what makes them function as a system.

People still thrive in a desert area

because of the knowledge they receive from the Lines.

A map for survival written in the sands.

♪ ♪

LAURENCE: Over the last century,

the world has marveled

at the many impressive achievements

of the Nazca people.

The Lines themselves are incredible,

but we can't forget about all of the other interesting

artifacts and features that have been found in this region.

There are some of the world's finest textiles

with incredibly elaborate designs.

There's beautifully made pottery.

MICHELE: There are hundreds of mummies that are

way better preserved than what we even see in ancient Egypt.

FORREST: And there's a centuries-old

underground water management system that works so well,

it's still in use today.

♪ ♪

LAURENCE: But there's also

a much more disturbing discovery.

MICHAEL: About 90 years ago, Alfred Lewis Kroeber,

an anthropologist, was studying in the area,

and what he found was a collection of severed heads.

MICHELE: So these heads are really well-preserved,

much like the mummies that we find

in this region, because of the lack of rain,

but what's interesting about them is that they have

holes in the center of their forehead.

And what we think these holes were for

is to put a string so that the head could be carried.

FORREST: Experts have long believed that these are

trophy heads, taken from rivals during war,

and then carried around and put on display.

Some heads are even found next to full mummies,

and researchers believe that a person might be buried

along with the trophy heads they collected in life.

LAURENCE: For nearly a century,

these heads are thought to belong

to enemies of the Nazca.

MICHELE: But years later, a team of scientists, in 2009

undertook some studies on these trophy heads

by using strontium analysis,

which can tell you where a person

was originally born, how that water in the ground was

incorporated into their bones and into their teeth.

They were able to tell where these heads originated.

Come to find out, the severed trophy heads

come from other Nazcans.

♪ ♪

LAURENCE: The finding leads some archeologists

to completely rethink the Nazca Lines.

We have a feeling the Lines are linked to rituals

or spirituality somehow, and we have a feeling

they are linked to the precious resource of water.

This new theory takes all of that into account,

plus the fact that we now have evidence

of local natives being beheaded.

MICHAEL: What does this mean? Well, according to archeologists

Donald Proulx and Corina Kellner,

what you have is a situation where the Nazca Lines

could be connected to ritual human sacrifice.

♪ ♪

FORREST: If you examine the images

on pottery and textiles from the Nazca,

trophy heads are everywhere.

Sometimes they're shown with plants sprouting

from them, which indicate they were likely buried

to increase agricultural fertility.

As we know now, these are local Nazcans.

They're not people from other areas,

so they presumably were not taken in war or battle.

These are people who have freely participated in the process

and in the ritual to help their own community.

LAURENCE: According to this theory,

the venue for these rituals is the Nazca Lines.

When we look at the geometric figures,

we realize there are these giant open spaces,

and these are potentially the arenas

for these ritual sacrifices,

whether they were battles that were played out

or other ritual actions.

In the Andean culture, warfare is actually linked to fertility,

and the losers of battle are sacrificed to the gods

to help with that fertility.

FORREST: This is all part of a religious attempt

to draw in water.

As the team dates the trophy heads,

they feel more confident about this theory,

because, right when the major drought hits the region

the number of trophy heads increases dramatically.

They start doing this ritual more and more in desperation.

LAURENCE: In 2022, a Polish research team finds

further proof to support this theory.

FORREST: This team tests hair samples

from the Nazca trophy heads

and finds that, before their deaths,

the victims ingested San Pedro cactus,

which contains mescaline.

MICHAEL: Right before the victims were killed

or sacrificed, as part of the ritual,

they were given this hallucinogen to prepare them.

FORREST: You find images of the San Pedro cactus

everywhere in Nazca iconography.

FORREST: This plant is clearly important to their religion,

and now we have proof that it's involved

in their rituals of taking trophy heads.

MICHAEL: The idea is that the Nazca would gather

at the Lines in these ritual spaces.

They would participate in the rituals,

ingest the hallucinogenic drug.

This would put them in a trance-like state

and prepare them to engage in the ritual battle.

At the end of the battle, the trophy heads would then be

buried with the hopes of inspiring

the gods to bring water to the area.

LAURENCE: But this is far from the final word

on the Nazca Lines.

FORREST: Maybe the Lines were ritual battlefields,

but I don't think that's all they ever were.

There's a good chance they serve multiple functions.

It's like roads today.

Yes, they move people from one place to another,

but we also stage parades down them.

We block them off for music festivals.

We bury our water pipes beneath them.

This seems like a more logical way to view the Nazca Lines.

MICHAEL: Are we ever really going to know

what the Lines were used for?

Probably not, and that's okay.

That's what's exciting about them.

But one thing we definitely know

is the amazing feat of engineering

that these Lines represent.

They were clearly very, very important

to the people of the time.

They cared deeply about them,

went to great lengths to build them,

and it is a real testament to human ingenuity, creativity,

and ability to build amazing things.

Despite their 2,000 year-old history,

more Nazca Lines are still being discovered.

A never before seen cat figure was found as recently as 2020.

Perhaps new evidence can finally reveal their true purpose.

I'm Laurence Fishburne.

Thank you for watching "History's Greatest Mysteries."

♪ ♪