All language subtitles for The.UnXplained.S08E11.1080p.WEB.h264-EDITH_track3_[eng]

[William Shatner] A legendary
treasure of gold

carefully hidden for 500 years.

A terrifying tower of skulls

marking the madness
of a once-great empire.

And rare artifacts
believed to invoke

mystical and frightening chaos.

Five centuries ago, in what is
now modern-day Mexico,

the Aztecs built one
of the most powerful empires

the world has ever seen.

It was a sophisticated society

focused on engineering,
agriculture, education, and

a brutal religious practice
that included human sacrifice.

But despite their immense power,
much of the Aztecs' history

has been lost or destroyed,

leaving only fragments
to piece together

a once-mighty civilization.

What mysteries are
yet to be revealed

about the Aztec Empire?

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

♪ ♪

[Shatner reads on-screen text]

This expansive metropolis
is the largest city

in North America.

And hidden beneath
the colonial-era buildings

and modern architecture

lie the ruins of a once powerful
and feared civilization.

From the 14th to 16th century,

this place was known
as Tenochtitlán,

the great capital
of the Aztec Empire.

It's a very modern city,
Mexico City, and yet,

just below the surface,

is this great history
of the civilization

that founded the city.

It's called Tenochtitlán.

And underneath
the ground in Mexico City,

there's temples,
there's pyramids.

Every time
you go to build a road,

who knows what you'll discover?

Because somewhere
around the 13th century,

the Aztecs appeared
in central Mexico

and very quickly built
this massive, powerful empire

that so fascinates us, but
about which we know so little.

[Shatner] Only 500 years ago,
the Aztecs

were the last great civilization
in Mesoamerica.

So why is their culture
such a mystery to us?

Many point to the Spanish
invasion led by Hernán Cortés,

where, from 1519 to 1521,

a campaign was launched
to destroy

the mighty empire.

[Buddy Levy] At the time
of the Spanish arrival...

...the Aztecs controlled
a large swath of Mesoamerica...

...reaching from
what is now Mexico City,

all the way down
to the border of Guatemala.

It was run by Montezuma in 1519.

He's been ruling the Aztecs
for 18 years or so.

He's treated as a god.

He has effective control
over many millions of people.

But ultimately,
the Spaniards came in,

and they would
raze to the ground

and set ablaze

everything that reminded them
of the Aztecs,

and that was devastating.

The Siege of Tenochtitlán

actually takes about 80 days.

They physically
buried some of it.

The Spanish built buildings

over the top of existing
Aztec infrastructure.

They eradicated
culture and language,

and because of that,
we have only fragments.

[Lynne McNeill] What we
don't know

about the Aztec culture

is so much bigger
than what we do know.

So much of what we know
about the Aztec Empire

we know from the people
who destroyed it,

from the conquistadors
from Spain.

And so, we can't be sure

how much interpretation
was being made there,

how much exaggeration,

how much work was being done

to justify the complete
destruction of this culture.

[Shatner] While much
of their history was destroyed

or rewritten
by the Spanish conquest,

there are a small number

of authentic Aztec
illustrated manuscripts,

called codices, that survived,

offering a glimpse
of the mighty empire.

And according to scholars,
before it was destroyed,

the Aztec capital
of Tenochtitlán

was a true wonder to behold.

[John Verano] The origin
of the Aztecs

is part myth and part history.

Uh, but most everyone agrees
they were

a nomadic hunter
and gatherer group

that settled on the banks
of Lake Texcoco.

In the early 1400s,

there was
a natural island there,

and then,
they expanded that island

that eventually became this
amazing city of Tenochtitlán.

When the Spanish
first saw Tenochtitlán,

they were just amazed.

The city itself was-was clean
and beautiful.

They had canals.

They had raised fields
where they grew

crops very efficiently.

I don't know if anyone
has figured out

how they acquired
their technology.

Tenochtitlán was larger than
just about anything in Europe,

perhaps except for Paris.

We estimate that
it had somewhere between

150,000 to 250,000 people.

It was planned along a grid

that was connected
by causeways to the mainland.

It had two
flourishing marketplaces.

There was a compulsory
education system.

And, very importantly
for the Aztec people,

it was seen as being the literal
center of the universe.

[Tok Thompson] We know
the Aztecs had math.

We know they had astronomy.

We know they had
religion and artistry.

They had this
huge agricultural system.

Fresh water, magnificent
palaces and terraces.

They were a very unique culture.

But the Aztecs were
a fairly short-lived empire

that still captures
our imagination

in part because of
some of their proclivities

for human sacrifice,
for their interest in death.

But there's a lot of unanswered
questions about the Aztecs.

We lack sort of
those-those fundamental

texts from the Aztecs.

[Shatner reads on-screen text]

Utility workers
digging at a site

in Mexico City's historic center

uncover a massive,
circular Aztec stone

depicting a dismembered
and beheaded goddess.

This astonishing discovery
launches ongoing,

official excavations,

which reveal what is considered
the holiest site

in Aztec society,

the great temple
of Tenochtitlán...

...Templo Mayor.

[Verano] Templo Mayor is
the largest monument

in the sacred precinct,
the center of Tenochtitlán.

And, uh, it was built
in the late 1400s.

It was an impressive structure

that stood perhaps
200 feet high or so.

It was a twin temple dedicated
to two of the Aztec gods.

On one side was Tlaloc,
the god of rain or water.

On the other side
was Huitzilopochtli,

the god of war
and the Aztec principal deity.

[David Carrasco] The excavation
of the great temple

is a gift
that never stops giving.

Imagine that,
in the last 40 years,

this excavation has continued,
and every year,

sometimes every month,
sometimes every week,

something sensational
and significant has been found.

The Aztecs actually buried
in the temple

over 200 offerings,
some in boxes, some in the open.

And these were offerings
to make the divinities

protect and nurture the Aztecs.

The whole Aztec world
was deposited

in the floors
of the great temple,

but you know,
they've only excavated, uh,

ten, 15% of what's there.

So, there's a great deal
to be explained in the future.

[Shatner] With each excavation,
clues to how the Aztecs lived

are carefully pieced together.

But there is one
surprising mystery

that has been eluding
academics for years.

It is the simple question:

where did the Aztecs come from?

The term "Aztec"
comes from their homeland,

which is a place
they called Aztlán.

And Aztlán
we don't know much about.

We know that
it was in the north,

and we know that
it took 250 years

of wandering to get to the site
of present-day Mexico City.

The location of wherever they
were coming from is a guess,

but they certainly
came from somewhere.

[Shatner] It's puzzling
to think that so little

is known about the life
and origin of the Aztec people.

But perhaps the truth
of their mysterious homeland

can be found in
a modern-day quest to find

the lost treasure
of King Montezuma.

[Shatner reads on-screen text]

Montezuma II,
the last true Aztec emperor,

welcomes Spanish conquistador
Hernán Cortés into his city.

Soon after, the great king
is taken captive

and Cortés turns his attention

to the empire's greatest prize:
its vast treasure.

When we meet Cortés arriving
at the shores of Mexico,

um, he's driven
by a lust for gold.

So, while Cortés and his men
are in the palaces,

remarkably,
one man finds this room.

It's a giant room, and it houses

the spoils and tribute
and treasure of

many Aztec leaders
over the centuries.

And this place is filled
with gold, silver, jade.

It's amazing, and

in today's value,
probably worth--

the gold alone-- on the order of

three to five billion dollars.

And so, they start to pack
some of this stuff away.

They're basically pillaging
Montezuma's treasure room.

[Geiger] Obviously, the Spanish
made away with some treasure.

Uh, but at least in the story,
quite a lot of it was lost.

It was moved by the Aztecs,
taken somewhere else

for protection,
for safekeeping.

But what happened
to the lost treasure?

That has given rise
to centuries of

hunting for the lost treasure
of Montezuma.

[Shatner] For nearly 500 years,
treasure hunters have searched

for the lost treasure
of Montezuma

with nothing to show for it.

But remarkably,
an intriguing discovery

in the heart of Mexico City
would reignite the hunt.

[Geiger] In 1981,
in Mexico City,

a construction project
is going on

and a 4.4-pound gold bar
is discovered.

And they're able to use
X-ray technology

to determine when this gold
was pounded into a bar.

And what they find out is
it comes from the period

of Cortés,
that it is almost certainly

part of Montezuma's treasure,

that it was pounded
into a gold bar

so that it would be easier
to ship back to Spain.

And what that proves

is that there was
Montezuma's treasure,

that the treasure is real.

[Shatner] If one piece
of gold survived,

could far more still be hidden?

According to the Dillman family,
the answer is yes.

And their ambitious quest
for Montezuma's treasure

has become
a multi-generational tradition.

That is amazing.

I'm a third-generation
treasure hunter.

I was literally born into this
quest for truth and treasure.

For as long as I can remember--
five years old, maybe sooner--

I was sitting at the dinner
table with my uncles,

John and Paul,
and my grandfather,

listening to all
the treasure stories.

When I was about eight years old

is the first time
that I got to go out

actually on a real adventure.

We discovered
an ancient stone tablet.

We found ancient pottery
filled with turquoise.

We found netting
that was made of llama hair.

And so, I have held on

to that childlike feeling
and experience.

[Shatner] Perhaps one
of the reasons Montezuma's

lost treasure
has never been found

is the fact that--
according to researchers--

it could be anywhere from Mexico
to the American Southwest.

But after generations
of family research,

Dan Dillman believes

he's narrowed it down
to a single location.

[Dillman] You have to imagine
the amount of wealth

and treasures
that were being moved.

It wasn't all moved at one time,

and it wasn't all moved
just from one location

to its final burial place.

We believe Chaco Canyon
was a location

where the treasure was stored
as it was being moved.

And then,
we have Montezuma's Castle

as a location as well,
where treasure was being moved.

But there is one location

that is special
out of all of these places.

This one location
we believe is in Kanab, Utah.

[Shatner] Could Montezuma's
treasure be hidden

in Kanab, Utah?

It's a curious theory,

but Dan Dillman is convinced
this remote, picturesque region

holds an even greater secret
than the treasure itself.

He believes this area is Aztlán,

the mysterious, ancestral
homeland of the Aztecs.

Some will say,
"How could Aztlán be Utah?"

We have the Disturnell map.

The Disturnell map
clearly points out, in Utah,

that it is the ancient
homeland of the Aztecs.

That is on
our own government maps.

Why is that?

Because the Mexican government,
during the Treaty of Guadalupe,

they had demanded
that their homeland

be documented
so that they can never say

that this wasn't
the homeland of the Aztecs.

It's documented
in our government records,

but it has gone unnoticed
for generations.

And so, I believe,
before the Spanish arrived,

Montezuma began hiding
the treasure

and moving the treasures north,

back to their homeland
of Aztlán,

and we are there
investigating now.

[Shatner] Could the Aztec Empire
have originated in Kanab, Utah?

And if so, could what remains
of Montezuma's great wealth

have been hidden there
for safekeeping?

Well, after decades
of searching,

Dan Dillman believes
he may have uncovered something

truly extraordinary.

[Dillman] We've used drones,
we've used lidar,

and we've also used
a good old-fashioned shovel.

And we have now discovered
an ancient wall

and an ancient tunnel system.

So, my son and I decided
that we would build a rover.

We needed to somehow
get a camera in there

and start investigating.

And guess what we've discovered?

In our cave...

...near the end
of the ancient wall,

we've discovered a stone box.

This discovery, I believe,

is gonna help to prove
that we are one step closer

to finding Montezuma's treasure.

[Shatner] For now,
the mysterious stone box

remains sealed until Dillman can
secure permission from multiple

landowners to continue
his excavation,

but he remains optimistic
that his family's dream

will soon be realized.

Almost every other treasure
that has ever been spoken about

has been myths or legends.

It could even be oral history.

But Montezuma's treasure
has been witnessed.

Words cannot describe
the feeling I would have

in the moment we find a portion
of Montezuma's treasure.

It's exciting to think
that the Aztecs'

legendary lost treasure
may one day be unearthed.

But there's another
recent discovery

that actually is quite alarming.

It's a disturbing monument
made with human bones

and stacked so high

it's called the Tower of Skulls.

[Shatner] Based on
surviving documents

and archeological evidence,

we know the Aztecs
worshipped multiple gods.

They revered gods
of the Sun, the night,

the rain, and the crops,

believing that
these powerful deities

sacrificed themselves
to create the world.

And in return, the Aztecs
believed that it was their duty

to honor and nourish these gods

with the ritual
of human sacrifice.

One of the things that really
stands out about the Aztecs,

that people often remark upon,
is their proclivity

for sacrifice,
including human sacrifice.

Now, this is something that was
already certainly a big part

of Mesoamerican civilization,

but the Aztecs take this up to
really a spectacular new level.

Maybe 100,000,
200,000 people were coming

to watch these spectacles.

You would march these people
up the stairs

to these top platforms
of these temples.

A priest would brandish
a giant, gleaming,

glinting obsidian blade,

impale the blade
into the chest, cut down,

remove the still-beating heart
from the sacrifice victim,

hold it up to the awed throng,

and then they would
toss the victim

tumbling down these incredibly
steep stairs at their feet.

[Shatner] Why would
a sophisticated civilization

that had astronomy,
mathematics, libraries,

and fine art engage
in such a savage practice?

[Carrasco] The Aztecs
didn't have a word "sacrifice."

The word that they used
for these ceremonies

is "nextlaoaliztli,"
which means "a debt payment."

And in Aztec theology,

the most meaningful, powerful,
potent debt was blood.

And so, in the Aztec thinking,

these sacrifices were ways
to maintain the cosmos

through the ritual
bloodletting of a person.

They honestly believed that,
if they stopped making

sacrifices to honor
Huitzilopochtli,

who was their principal deity,

the Sun would stop
going around the Earth,

and it would be
the end of the world.

Some sacrifices were done
to affirm their political power,

but it would also be a way
to please the gods.

Scholars have tried
to do the math

based on the number of killings

that the codices tell us
happened in each festival,

and then the number
of festivals per year,

and it's anywhere from 10,000 to
80,000 ritual killings per year.

One of the codices describes

the overwhelming smell of blood

when, at one time, 20,000 people
were killed at once.

But we have so few details
about the reality

of the scale of human sacrifice
that was taking place.

[Verano] Many say that
the Aztecs have been demonized

up to this day
for the number of sacrifices

they supposedly did
and for the brutality

of taking people's hearts out
and so on.

That's one side.
There's another side that

has been called
the sacrifice deniers.

Those who say
the Spanish made this all up.

[Shatner] Is it possible
the Aztecs murdered

tens of thousands of innocent
souls to honor their gods?

Or is it all just propaganda?

Perhaps clues may be found

at the holiest site
in the Aztec Empire.

The ruins of Templo Mayor.
Mexico City, 2015.

Archaeologists excavating
an area just north

of this Aztec temple
are shocked to discover

a tower of skulls.

[McNeill] Excavations
into the Templo Mayor

start uncovering

these buried towers of skulls

that, when counted,
actually kind of line up

with some of those
extreme numbers

that were given in the writings
of the conquistadors.

Literally architectural designs

that, instead of stones,
feature human heads,

and basically creating
a true theater of death.

[Verano] The archeologists
very quickly realized

they were on top
of a major discovery.

Everyone agrees this must be
the great tzompantli

that was described in
the early 1500s by the Spanish,

a construction
full of human skulls.

And the skulls were from victims

who were sacrificed
at the Templo Mayor.

They were decapitated.
Their heads were cut off.

The heads were then defleshed.

And they found more than 100
so far in this first tower,

uh, and they've only
excavated part of it.

There's a substantial
percentage of women

and also some children
as young as three years.

I read that and I went,
"Wow. How do we explain that?"

[Shatner] This horrific tower
of skulls could be considered

confirmation of acts
of brutal human sacrifice.

But what was the purpose
of creating

such a grotesque structure?

[McNeill] Was this
to instill fear

in the hearts of their enemies?

To show their incredible power,

the reach of this empire?

"Look how many people
we can kill

and how much resources
we can put

toward displaying them
in this particular way."

It may also have been an act

of ritual honoring to the gods.

So, the fact that
we found one of these

tzompantli, these skull towers,

is it likely that
there are many more

somewhere underground
waiting to be discovered?

[Levy] It's interesting
to contemplate

what these skull towers
and skull racks were for.

What was their purpose?

We don't know, because
a lot of it is speculating

on what some
of these rituals involved

and why they would do them.

We may have only scratched
the surface of what

was really happening,
and it was happening

at a larger scale
than we ever thought possible.

Why did the Aztecs
create the tower of skulls?

While it seems it was
undoubtedly important,

based on its construction,

the true purpose
may never be known.

And the same can be said
for a collection

of mysterious
musical instruments,

whose blood-curdling sounds
sing songs

of terror.

[Shatner] Berlin, Germany.
The Ethnological Museum.

Among thousands of relics
is a collection

of small and unusual
clay instruments

carved in the shape
of a human skull.

These seemingly harmless objects
are believed to be the source

of powerful,
fear-inducing sounds,

which is why
researchers call them

Aztec death whistles.

[Arnd Adje Both] These are
the Aztec death whistles.

We know that
they were produced between

the 14th and the early 16th
century from Central Mexico.

They are in the form
of a human skull

probably because
they are related

to the lord of the underworld,

portrayed with a human skull.

They are wind instruments,
but they are very special

because of their distorted
kind of sound that they produce.

[whistle blowing]

I'm now playing them in a way

that the sound
resembles the wind.

If I play more strong...

[high-pitched whistle blowing]

...the sound becomes
more harsh and more shrill.

It's just not a howling wind
which is heard, no.

It's a mythological wind.

There is a study
recently published

where people had to listen
to the sound

played in different ways.

Most of the people experienced

the sound as negative,

as aggressive.

Something like,
"Wow, this is scary."

[McNeill] It's hard to call
them musical instruments.

When we think of whistle,
we might think of something

upon which you
might play a melody.

And that's not what these appear
to do. They make a noise.

Almost a supernatural
wind howling.

[howling whistle blowing]

But it's unknown
really what role

they played in Aztec society.

[Shatner] Based on modern
scientific research,

the sounds produced
by this strange instrument

clearly elicit fear
in the human brain.

But what purpose did the Aztec
death whistle really serve?

Perhaps the first clues
came in Mexico City

during the excavations

of the ancient Aztec site
of Tlatelolco.

As outlined
in a fascinating book

by Salvador Guilliem Arroyo,

archeologists discovered
a 500-year-old victim

of human sacrifice

buried with
a skull-shaped whistle

in each hand.

Aztec death whistles were found
with an obvious ritual killing,

the body of a young man,

who was found
in a temple decapitated.

And we can assume that the sound

that a death whistle makes
was somehow important

because of their placement
in this ritual sacrifice.

It's one thing
to listen to the sound

out of context,

but when we imagine it
in context,

we're in a temple,

there are people
being sacrificed,

hearts being removed.

These gifts to the gods
being provided.

And the soundtrack is not just

the human sounds being made,
but this unearthly wind.

Depending on how many people
might be playing them...

...this could be an incredibly
overwhelming sensory experience.

Which really would form
the basis

of a really powerful ritual.

[Thompson] These sacrifices
were a huge part of,

you know, religious
and ritual events.

They'd always have sound
accompanying them and music,

so it might have just been
part of the atmosphere

in some of these
particular rituals.

On the other hand,
we don't quite know

how these were used,
but they have captivated

people because they remind us
that the Aztecs

were really, really focused
on death and on skulls,

uh, and on that-- really
on that moment of dying.

[Shatner] Did throngs of Aztecs

once play these
otherworldly instruments

during ritual human sacrifices?

It's certainly
a plausible theory.

But others have wondered,
based on the unsettling sounds

that these
death whistles produce,

were they played
to terrify their enemies

on the battlefield?

As a tool of warfare,
they would be very effective,

because if you think
of maybe hundreds

or a few thousand
running warriors

blowing these things,

the noise would be incredibly
deafening, terrifying.

And it would also
amplify the sound

so that the enemy might think

that there are
many more warriors

than there actually are,

and that they're coming
from different directions.

Now, they haven't really
discovered any at battle sites,

but that doesn't mean
that they won't.

These skull-shaped
Aztec death whistles,

I have to say,
is one of the more remarkable

a-and also inexplicable
and tantalizing

elements of the Aztec culture

that we don't fully
understand yet.

[Both] When it comes to
an archaeological culture,

we only have
the material remains,

maybe we have
some textual evidence,

maybe we have
some pictorial evidence,

and that's it.

We just have to put together,
scratch together what we find

and make
an interpretation out of it.

And this applies to all aspects
of an archeological society.

Of course, including the music,
the musical instruments,

and, in particular,
the death whistles.

There are no definite answers.

Were Aztec death whistles
used in religious rituals?

Or were they
sophisticated sonic weapons

meant to elicit fear
in the hearts of their enemies?

Whatever the case,
there are other Aztec artifacts

said to be imbued
with incomprehensible powers.

Like mirrors made of obsidian

that offer a looking glass
into the future.

[Shatner] The British Museum.
London, England.

Established in 1753,

this revered institution
houses ancient art

and artifacts
from all over the world.

And one of the most mysterious
objects in the collection

is a circular mirror
of obsidian--

a type of volcanic glass--

with a mystical story.

It is known as
"The Devil's Looking-Glass,"

and in the 16th century,
it belonged to an advisor

of Queen Elizabeth I,

an intriguing gentleman
named John Dee.

John Dee was a scholar
at Cambridge University,

and he was one
of the best they had.

He studied mathematics,
astronomy, all sorts of things.

He became interested in alchemy.

He did readings
of the stars, astrology,

and he was basically

the greatest magician
of his age.

And John Dee claimed that
his black, obsidian mirror

once belonged
to the Aztec high priest.

On top of a temple
in the Aztec Empire,

the high priest
would look into it

and see visions,
in the same way

as somebody might use
a crystal ball.

And so, John Dee,
with his black obsidian mirror,

attracted the attention
of Queen Elizabeth I.

She not only hired him
as an astrologer,

but she made him
one of her official advisors.

And so, at the time,

he became probably
one of the most important

and powerful people in England.

[Shatner] Is it possible that
John Dee's obsidian mirror

belonged to
an Aztec high priest?

Remarkably, in 2021,
a geochemical analysis

determined that this
obsidian artifact was, in fact,

consistent with other objects
from the Aztec Empire.

Some of these obsidian mirrors
found their way across

the Atlantic
to collections in Europe.

In terms of what we know
about the Aztecs,

obsidian was an incredibly
important commodity,

and peoples of that region
just relied on it

for all their utilitarian tools,

as well as their weapons.

One thing that
the Aztecs would make

out of obsidian are mirrors.

Because if you polish obsidian,

it's almost like looking
into a crystal ball.

So you can go into, like,
a trance-like state

and see visions, uh,
within the obsidian mirror.

And so this was
a really important

religious object
in Aztec society.

[Carrasco] The idea is that,

when you look
into the obsidian mirror,

you don't just see yourself.

What you see is an angel,
a spirit, an animal helper,

some other kind of ally

that can help you divine,

understand what
your destiny is going to be.

One of the greatest
Aztec divinities

is called Tezcatlipoca,

or Lord of the Smoking Mirror.

And the idea was that
he could see into people.

He could see into trees.

He had this ability to perceive,

uh, below and beneath
the surface.

And that's what
the obsidian mirror did.

[Phillips] The interesting
thing about these

obsidian mirrors
in the Aztec world

is that they were made
from volcanic glass,

and the Aztecs believed

that other worlds existed
inside volcanoes.

And the obsidian mirrors

gave them access to this world.

Like a crystal ball that you can
see a future event in it,

or you can glimpse something
from another world,

the obsidian mirrors were
thought to also be able

to be used
to call things through.

It was a portal
to another world.

[Shatner] While there
are surviving

16th-century manuscripts,
like the Florentine Codex,

documenting many Aztec beliefs,

the idea that
polished volcanic glass

can channel mystical powers
is hard to believe.

And yet, some point
to an intriguing legend

when John Dee
allegedly saved England

with his Aztec obsidian mirror.

According to one of
Dee's very close friends

and colleagues,
a man called Robert Recorde,

Dee used this
obsidian mirror to predict

the coming Spanish invasion
in the 1580s.

But what's more than this,
Recorde tells us that

he looked into the mirror

and he was able to actually
bring about storms

that sank the Spanish Armada
in 1588 and save England.

[Shatner] Did John Dee's
magic mirror summon a storm

and save England
in the 16th century?

Who knows?

At the very least,

these mysterious
obsidian objects

provide a fascinating glimpse

into the lost world
of the Aztecs.

[Shatner] 30 miles
northeast of Mexico City,

the former Aztec capital
of Tenochtitlán,

lies the ruins of Teotihuacán.

Spanning nearly eight
square miles,

this ancient metropolis features
ceremonial avenues, plazas,

and three towering pyramids
laid out with uncanny precision.

The Aztecs believed
this is where

their gods sacrificed themselves
to create the Sun.

Even Montezuma himself

visited this mystical site
every 20 days.

But what's truly surprising
about Teotihuacán

is that the Aztecs
arrived here more than

a thousand years
after it was built.

I'm unbelievably intrigued
by Teotihuacán,

because it was a ruin

by the time the Aztecs
arrived in 1300,

and we don't even know
who built this place exactly.

It's all speculation.

Much less is known about
the builders of Teotihuacán

than about the Aztecs.

[Carballo] Teotihuacán
was a monumental city.

To the later Aztecs, Teotihuacán
was seen as a place of creation.

And so, they gave it
the name Teotihuacán,

which is loosely translated as

"place of the gods."

The ruins of Teotihuacán
were 1,000 years

before Aztec society took off,

but laid a lot of the templates
that we know for Aztec society.

They drew on these
earlier civilizations

as part of their
templates for creating

their own cities
and sacred precincts.

[Shatner] While the identity of
Teotihuacán's ancient builders

remain one of archaeology's
great unsolved mysteries,

if this site really did inspire

and help shape the Aztec Empire,

what secrets might this
awe-inspiring place

still reveal?

In 2003, Sergio Gómez and team

discovered this
shaft opening underneath

the Ciudadela and
the Feathered Serpent Pyramid,

and then they found
this chamber leading over

100 meters to underneath
the center of the monument,

and that hadn't been
entered and looted.

And it included
these spectacular offerings.

[McNeill] There are artifacts,
objects in this tunnel

that had not been seen
by human eyes for 1,800 years.

And one of the most
remarkable findings

at the very end
of this tunnel is this

recreation of the world
made out of the materials

that people could
find around them.

So, we see bodies of water
replicated in liquid mercury.

We see iron pyrite
to replicate the experience

of standing under
the night sky filled with stars.

I mean, this is unbelievable.

And what we know
about it is so small.

[Shatner] According
to researchers,

only around three to
five percent of Teotihuacán

has been excavated.

It is just one of many sites,
artifacts, and treasures

that are yet
to be truly understood,

just like
the once-mighty Aztec Empire.

One of the things
that fascinates us

about the Aztecs
is how little we know,

because we should know
so much more.

We know that they were
heavily structured,

that they had a clear hierarchy
that had a powerful

religious element to them.

They have so many things
that model

like they were
a great European kingdom.

And yet, there's gaps,
and those gaps alone

are what make the Aztec Empire
so fascinating to us.

So much of the Aztec history
was covered up, obliterated,

razed by the Spaniards,

and it is only now,
in the last decade--

or even more recently--
being unearthed.

And it's really interesting
to wonder what's left.

Every new discovery about
the Aztec Empire seems to reveal

a civilization that was far more
sophisticated than we imagined.

And as archeologists
continue to discover pieces

of the ancient past,

it appears that only more
questions are uncovered.

Were the Aztecs the true masters
of hidden knowledge?

Or guardians of ancient secrets

inherited from another
advanced culture?

Well, it's a fascinating theory,

but for now, the lost history

of this once-mighty
empire remains...

...unexplained.

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