NARRATOR: Deep inside the labyrinth
of a flooded cave system...
MAN: All of a sudden, the floor just drops.
NARRATOR: Divers come across human remains.
MAN: You can see these dark eye sockets
kind of looking back at us.
NARRATOR: And the bones of giant prehistoric creatures.
MAN: Saber-tooth cats, bears, giant ground sloths.
NARRATOR: Discoveries that could revolutionize
our understanding
of how the first humans came to the Americas.
MAN: They must have come here another way.
¶ ¶
ALBERTO NAVA: We have 800 miles of underwater tunnels
that have been mapped.
We think there's another half still to be discovered.
¶ ¶
NARRATOR: A team of divers is exploring
the world's largest underground flooded cave system.
ALBERTO: It's like a labyrinth of tunnels everywhere,
almost like a Swiss cheese in the ground, full with water.
NARRATOR: Their aim: to survey this lost world,
sealed off from humanity since the Ice Age.
¶ ¶
ALBERTO: The Yucatán is special,
because all the cave here were once dry.
We know this because of the stalagmites and the stalactites
which only form in a dry cave.
About 12,000 years ago, at the end of the Ice Age,
the ice sheet melted and the cave began to flood.
NARRATOR: Now, these flooded caves
pose grave risks to the divers.
ALBERTO: Caves can be very dangerous.
You have, you know, going in an environment
where, if you have a problem, you cannot ascend.
The tunnel that you're traveling is totally dark.
Your lights now not have a way to see.
If you go in a small area,
you could get trapped inside the cave, so there's a lot of risk.
NARRATOR: The team's goal is to map this complex network.
ALBERTO: When we go into these tunnels,
we do a very simple map of the cave.
Then we bring the camera,
and then what we do is we take a lot of images.
NARRATOR: It's taken 150 hours to map as far as this point,
and now the divers stop.
ALBERTO: All of a sudden the floor just drops.
We have these really powerful underwater lights,
and all you can see was darkness.
So, like, the biggest, darkest hole we've seen on the cave.
NARRATOR: Using the divers' own data and imagery,
the scale of the abyss becomes clear.
¶ ¶
ALBERTO: If we were to drain the water,
we would see this bell-shaped structure,
maybe like a football field, stadium kind of size.
¶ ¶
NARRATOR: They name the vast cave Hoyo Negro;
Black Hole.
ALBERTO: As we descended into the pit,
we were moving our lights,
trying to figure out what was down there.
¶ ¶
NARRATOR: Anything Alberto and his team find here
will come from prehistory, when the abyss was a dry cave.
¶ ¶
ALBERTO: And then, then we saw a bone.
It was a really long, tall bone.
We moved around it, and then we saw another bone.
We started noticing that there were,
there were remains all over the place on the floor.
Whatever they were, it has to have been a really big animal.
We knew we found something really important here,
so we mapped everything in the cave,
recorded the exact locations of the bones and took photos,
and then we sent all our data to our colleagues in California.
¶ ¶
DOMINIQUE RISSOLO: Our goal is to capture these places,
these wild places, using our visualization systems.
¶ ¶
VID PETROVIC: Okay, I'm just gonna go through
the different views.
¶ ¶
So, we're now just kind of reliving the dive paths.
NARRATOR: In 2014, Dominique Rissolo and his team
begin to process the divers' mapping data and images.
Their aim is to create a 3D digital replica of Hoyo Negro,
which they can explore from dry land.
DOMINIQUE: The divers have tremendous experience
in doing different kinds of documentation underwater,
and we're able to take all of those images,
and through computer vision algorithms,
translate them into a 3D model.
And it's really, essentially, a point cloud, a cloud of points.
VID: So far we have around 15 billion reconstructed points.
The exciting thing is it grows every year,
so every time they go diving, take pictures,
we run new reconstructions.
We just add to the set.
DOMINIQUE: The way that we can create
maybe a more photo-realistic 3D model
is by then texturing those points
with the original photographs.
So, these are high-resolution images
that can be essentially draped on to this 3D point cloud.
¶ ¶
DOMINIQUE: Wow, so, here we are at the bottom of Hoyo Negro.
JOEL POLIZZI: This is one of the most powerful
virtual reality systems in the world.
¶ ¶
Being inside the SunCAVE is similar
to being on the dive itself,
with the exception that you're able to be well lit.
You're able to see everything that you can't see.
DOMINIQUE: This is essentially an interactive digital twin
that enables us to come here and do virtual dives,
and sometimes even find new animals.
Finding new animals in a virtual cave, right?
So, exploring a real cave by using a virtual one.
¶ ¶
The first big animal that the divers came upon
was right here, this gomphothere.
It wasn't as if it was just this proboscidean,
this relative of the elephant.
It's such an incredible diversity of Ice Age fauna.
Bears,
saber-tooth cats,
giant ground sloths.
Just amazing!
So, Joel, if you take us sort of onto the wall of the cave here,
we can see this saber-tooth cat emerge, Smilodon fatalis.
Clinging to the wall we see, you know, another scapula,
of course, the scapula over here of the giant ground sloth.
Its ribs.
NARRATOR: By examining the bones,
Dominique's colleagues identify at least 16 Ice Age species.
DOMINIQUE: Whether they were looking for water,
or to build a den, or even to hunt,
these are massive animals
that were walking through these passageways,
coming to the edge of this precipice
and making their way to the bottom of this pit.
It's a really wonderful view into what the planet was like
at a time thousands of years ago.
As incredible as those discoveries were,
that wasn't the only thing they found that day.
ALBERTO: We were swimming at the bottom of the site,
looking at the animal remains,
and then all of a sudden my friend, Alex,
just moved his light
and he pointed in a particular direction.
NARRATOR: Within touching distance,
at the bottom of the vast, flooded cave system,
diver Alberto Nava and his team
are about to make the discovery of a lifetime.
ALBERTO: We see this beautiful cranium.
It's just sitting, sitting upside down.
You can see these dark eye sockets
kind of looking back at us.
DOMINIQUE: My blood ran cold.
I mean, my hairs stood on end.
ALBERTO: I don't think I'll find anything like that
in my exploration life.
This is probably the best it's ever gonna get.
DOMINIQUE: All these things come to mind.
Who was this person?
You know, how did they come to be here?
When did they arrive at the bottom of this pit?
NARRATOR: To help find the answers,
the team consults experts from around the world,
led by Mexico's
National Institute of Anthropology and History.
DOMINIQUE: We have now over 30 scientists
and engineers involved:
the paleontologists,
the archaeologists and anthropologists
who are all helping to put together this puzzle.
JIM CHATTERS: We have a fairly consistent
3,000-year offset between...
DOMINIQUE: As a project, we made the decision
to reach out to Jim Chatters,
who had the experience and expertise we really needed
to understand the significance of the site of Hoyo Negro
and everything it contained.
JIM: Well, you just don't see this, this kind of preservation,
so it's just unbelievable quality.
¶ ¶
NARRATOR: The first question on the team's mind,
"Who is this person at the bottom of the cave?"
¶ ¶
DOMINIQUE: I shared photographs of the discoveries,
and his eyes lit up.
I could see his hands trembling a little bit.
JIM: And here's our human.
The skeleton is, it's a diary of someone's life.
And it's especially a diary of their early years.
This is a really good picture here.
Here's the telling piece.
I can see, first of all,
that a feature in the base of the skull
called the "basilar suture" was still open,
and that tends to close somewhere around the twenties.
And it was not only a full-size skull,
but the third molars had already erupted.
So, it's a fully formed tooth, or nearly fully formed,
which puts this more than 15 years old.
In looking at this, right away I'm thinking 16 to 19 years
is the most likely age of this individual.
To determine the sex of a skull,
you're looking at how rugged it is, mainly.
In this case, what I did was I look at the mastoid processes,
and that's the position on the skull here
where the large neck muscles attach,
and they tend to be large in males and small in females.
And in this case, they were very small.
I asked Dominique if anyone had told him what he had there,
and he said, "No, they hadn't."
And I said, "Well, what you've got here
is the bones of a teenage girl,
and a bunch of really large megafauna."
This is the first time we have a human skull
in direct association with the skeleton of an extinct animal
in the Americas, period.
That's really exciting.
NARRATOR: Over successive dives,
the team finds and scans more bones
belonging to the teenage girl.
By 2013, they've documented her near-complete skeleton,
and she has become more than simply an archaeological find.
DOMINIQUE: Here we are in Hoyo Negro.
JIM: Yeah.
Wow!
I've always wanted to dive this.
This is about the closest I'm ever gonna come, I think.
¶ ¶
She's spread over about a 16-foot span here.
¶ ¶
What I stressed with the divers was that basically they needed
to remember the personhood of these bones.
ALBERTO: If you give it a name,
you become more caring about this skeleton,
and it goes from a skeleton to becoming a person.
We had a lot of candidates for names.
We decided to call it Naia.
¶ ¶
JIM: Naiads were water spirits in Greek mythology.
They were the female spirits
that watched over small bodies of water,
so it seemed a very fitting name for her.
NARRATOR: Naia's remains are found close to Ice Age mammals,
but that isn't enough to prove
that Naia herself is prehistoric.
JIM: Our goal with Naia was to collect a specimen
from the skeleton to use for radiocarbon dating.
¶ ¶
We chose to do one third molar,
because third molars are often very simply rooted,
and therefore easy to take out of a skeleton.
DOMINIQUE: There are a number of problems
inherent in carbon dating, and those can include contamination.
It was not a foregone conclusion
that we were going to get a viable date from Naia.
JIM: We ran dates independently in two laboratories,
fully expecting the dates
to be completely different from each other,
and it came back within 15 years.
And between those,
those translate to close to 12,900 years ago.
It was pretty exciting to find out,
because only one other skeleton at that time had dated that old,
and all that there was of that individual was one bone.
Not even a complete bone.
The fact that Naia's skeleton was so complete
makes her an incredibly rare find.
NARRATOR: And as the oldest near-complete skeleton
ever found in the Americas,
Naia could provide answers about early humans living here.
But to protect her remains,
the team must first remove her from the cave.
ALBERTO: So, it's been six, seven years of adventure,
and although we didn't really want to take any human remains,
we have to do it to protect it,
and that's kind of what the day is all about,
protecting Naia and her remains.
NARRATOR: The operation to recover Naia's fragile skeleton
begins with her skull.
It is fraught with risk.
JIM: Well, we're doing a pre-dive practice,
or the procedures drill.
NARRATOR: Jim rehearses the recovery with a replica skull.
JIM: My endeavor was designing
how Naia's bones were gonna be safely removed.
Your strongest part is here.
SUSAN BIRD: Mm-hmm.
JIM: Your weakest points are here and here,
so we want to protect them.
This was a big deal.
I mean, imagine, I'm the one responsible for making sure
that thing doesn't get destroyed in the collection process,
so I was just a little on the nervous side.
And just gently, chin first.
SUSAN: Okay. JIM: And release.
The reason Susan was the one to handle the bones
had in part to do with the fact that she had very steady hands,
but she also felt a linkage
to the young woman who was in the cave.
SUSAN: And I just feel very connected with her spirit.
I feel like she's been there a long time
and is ready to go home.
¶ ¶
ALBERTO: There was one chance, and we had to get it right.
¶ ¶
The moment Susan picked up the skull,
everybody's breathing stopped.
¶ ¶
JIM: That was a really tense three hours of waiting,
waiting to see if what would be in the box when it came up
was a complete skull or a whole pile of bone fragments.
¶ ¶
Here they come!
My, oh, my.
Okay, Susan's on the left, Beto's on the right.
¶ ¶
DOMINIQUE: She comes to the surface,
and you know that as an archaeologist,
you're never gonna have another experience like this.
I mean, this is it.
(sighs)
Okay, go ahead.
Okay, she's fine in there.
Nice! Ha.
I remember getting down and peeking in the end
and seeing a whole skull there,
and tremendous elation that came from that.
Welcome, Naia!
We got her out and we got her out whole.
ALBERTO: Jim Chatters, it's good to meet you.
JIM: Gracias, gracias. Good job, man.
I've been at this for 60-plus years,
and that was the top moment in all that time.
SUSAN: Hey!
JIM: We cried.
¶ ¶
NARRATOR: Naia's remains give the team
an unprecedented opportunity
to learn about America's early humans.
A key question is whether Naia is a direct ancestor
to modern Native Americans.
In a replica of her skeleton, Jim looks for clues.
JIM: The characteristics that jumped out at me
was the very distinct angularity to the back of her skull,
and the tendency for her face to project forward.
NARRATOR: These are not common features
of modern Native Americans.
JIM: The contrast with more recent Native American skulls
represented by these casts here.
Here's a female.
You can see a much more rounded skull.
The face, in a similar position,
is much more straight up and down.
NARRATOR: When the team turns
to facial reconstruction technology,
the mystery deepens.
JIM: What we got, we went from the printed skull here,
and then this is how she turned out.
¶ ¶
I didn't expect her to look like she did.
She almost looks like a South African bushman
from the Kalahari Desert, or someone out of Southeast Asia.
Her eyes are wider set, her nose is broader,
so those are all things that were different
from what I'm used to.
DOMINIQUE: There's a mystery then:
If she appears to be so different from the ancestors
of modern Native Americans, where did she come from?
NARRATOR: To find out, the team tests Naia's DNA.
JIM: When I got the result back,
I was very happy that we got a result,
but as happy as I was to get the result,
it was not the result I expected.
What it showed was that although Naia's skull seemed different
from modern Native Americans,
they still shared a genetic background.
They shared the same heritage.
NARRATOR: So, Naia is an ancestor
of modern Native Americans.
Now, the age of her skeleton,
dated to the very end of the Ice Age,
propels her into the center
of one of the hottest controversies in science.
How did she and her people get to the American continent?
JIM: So, part of the question about Naia
was can she help contribute to an answer to that question?
¶ ¶
NARRATOR: For decades, experts agreed
on how the first humans migrated to the Americas.
JAMES DELGADO: In school, studying archaeology,
I heard a great deal about the Bering land bridge.
¶ ¶
During the last Ice Age,
huge ice sheets blocked the land route from Siberia to Alaska.
But when the ice thaws around 13,000 years ago,
which is when Naia is living in the Yucatán,
it becomes possible for humans to walk into America,
and a group previously known as the Clovis people do just that.
LOREN DAVIS: The Clovis First model is that people came
into the Americas by way of migrating
through an ice-free corridor, exiting south of the ice,
hunting megafauna like mammoths and bison,
using a very specific kind of technology
known as a Clovis spear point.
JAMES: That view that this Clovis group were the people
that had come across the Bering Straits
and were the ancestors of modern Native Americans
became so fixed in archaeological orthodoxy
that to suggest an earlier date and other migrations
was scientific heresy.
NARRATOR: The question is, do Naia's people
travel to the Yucatán through the opening ice-free corridor,
or some other way?
¶ ¶
LOREN: The problem with explaining everything
as an interior migration,
that's just not an explanation that accounts for the facts,
and the facts are that people are south of the ice
before this ice-free corridor opens.
The earliest sites, for example, are actually in South America.
So, there's one in Peru called Huaca Prieta,
and there's another one in Chile
known as Monte Verde.
Stone tools, bones and charcoal from these sites
show that humans were in the Americas
at least 14,500 years ago,
more than 1,000 years before the ice melts.
NARRATOR: So, if ice is blocking the land route,
how do these earliest Americans arrive?
LOREN: They must have come here another way,
so that's why we're interested in looking on the coast,
'cause that is the easiest explanation
to explain how we can get people south of the ice
before this ice-free corridor opens up.
NARRATOR: In 1997, scientists begin to uncover evidence
of very early human habitation in this remote valley in Idaho.
LOREN: As people were migrating south along the coast,
they would have had ice to their left
and the ocean to their right,
and they would have encountered the Columbia River eventually.
They may have decided to just simply take a left-hand turn
south of the ice,
and penetrate into North America at that point.
And if they kept going upriver,
they would have made their way here to Cooper's Ferry.
NARRATOR: Loren and his students search for stone tools
that migrating humans may have left behind.
LOREN: Well, if this site was old enough,
we might actually find evidence of Clovis peoples,
but, sort of to my surprise, we didn't see that at all.
Did you see this thing?
What we did find instead
were these other kind of spear points,
and these are known as stemmed points.
Stemmed points look very different than Clovis points.
They have a little, small rectangular tab at the bottom.
That just made it very clear
that we have some other kind of cultural pattern
that's present at the site, at the same time
people were making Clovis artifacts somewhere else.
When we first found these, I really didn't have any idea
how old they were, so that was a big question.
Radiocarbon dating showed us that points like these
are 13,000 years old.
Some of them were older, 14,000, 14,500.
And it just blew our minds that this technology
could actually be as old as Clovis, and then even earlier.
NARRATOR: Some challenged this, but if those dates are correct,
that's 1,000 years before the ice-free corridor,
and at least 2,000 before Naia's time.
How might these people arrive?
Are the stemmed points a clue?
LOREN: The only other place that we find artifacts
that look like this during the end of the last Ice Age
are in the northern part of Japan,
on the island of Hokkaido.
NARRATOR: Loren believes this shows how early people
traveled into the Americas from the Far East,
via the Ice Age coastline and rivers.
LOREN: If we imagine that people might have been able to come
along the coastline, along the Northern Pacific,
into the Americas, we don't really need to look much farther
than Japan, the Russian Far East,
and they show us that there's a population already in place.
They are on the doorstep,
waiting to migrate their way into the Americas.
JAMES: It didn't mean that you'd have to sail
all the way across the Pacific or across the Atlantic.
You just island-hopped from bay to bay,
making your way, sometimes over a generation.
LOREN: As new sites are being discovered
that show us that people are south of the ice
before an ice-free corridor opens,
that requires us to really rethink things.
NARRATOR: To truly understand human migration,
Loren needs to explore the Ice Age coastline.
The problem is, it's now more than 400 feet underwater.
LOREN: How can we find the evidence out there
where it likely exists?
And that takes us offshore,
and we need to look beneath the waves.
LOREN: It's important to understand the coast
from an archaeological perspective,
because it could be the place that holds evidence
for the earliest peoples to come into the Americas.
NARRATOR: Loren Davis is searching for evidence
that early settlers use a coastal route
into the Americas,
but he's not looking at today's coastline
for a very good reason.
LOREN: During the Ice Age, the coast of the continent
looked very different to how it does now.
When the ice melted,
all that trapped water raised sea levels by over 400 feet,
so any evidence of early peoples living on the coast
are now deep underwater.
NARRATOR: And that means searching below the waves,
30 miles out to sea.
LOREN: Getting on this ship was a real breakthrough for us,
'cause it allowed us to then go out
and ground truth our theoretical ideas.
WOMAN: We are off the northeast of Heceta Bank,
which is off the central coast of Oregon.
LOREN: We went out to the very edge of the ancient coastline,
so these are areas
that are about 130 meters below modern sea level.
Oh, man!
Went off a cliff!
(woman chuckles)
NARRATOR: Loren one day hopes to find evidence
of prehistoric human settlements
on this ancient coastline.
The first step is to build an accurate picture
of the hidden Ice Age landscape below the waves.
LOREN: As sea level comes up,
it brings a lot of sediment with it,
and it will bury the ancient landscape that was once there,
so this obscures our view.
We really need a technique
that allows us to see into the seafloor,
and one of the tools that we use is called a sub-bottom profiler,
and what this does is it sends a sound pulse into the seafloor,
and it will reflect back an acoustic signal
that it then turns into sort of a depth map.
MAN: Could we track a line bearing 317 at 0.4?
NARRATOR: Merging the deep sea scans
with data from computer models
reveals a world not seen for millennia:
the shoreline of Ice Age America.
LOREN: If we were to lower the ocean
down to about 13,000 years ago, the position where it was then,
we would see a really different coastline.
We would be able to see river valleys,
we would see embayments, we would see a low mountain range.
It would be a broad coastal plain
that looks really different
than the rugged, mountainous coastline
of today's central coast.
JAMES: That's a landscape with estuaries full of marine life,
as well as seabirds and animals.
And with that, we would see this lost world,
the Americas as they were
at the time of initial human settlement.
¶ ¶
LOREN: This story of ancient coastlines under lower sea level
associated with the last Ice Age is not just an Oregon story.
This is a story that happens everywhere.
NARRATOR: Similar investigations
are being conducted all along the Pacific coast.
LOREN: As you go farther south,
San Francisco would have been an area
that isn't on the coast in the past.
That is, lowered sea level
would have taken it much farther away from its modern position,
so San Francisco would have been really sort of an inland valley.
¶ ¶
NARRATOR: Having accurate mapping
of North America's Ice Age coastline now allows Loren
to narrow his search for signs of early human habitation.
LOREN: So, if I'm a traditional hunter-gatherer, fisher person,
and I'm living on an ancient coastline,
where are the hot spots?
Where are the places that are gonna take care of me the best?
And the estuaries are really, really
important places for people.
I mean, there's more calories per square meter in an estuary
than almost any other place on the coast.
NARRATOR: What really happened remains unclear,
but Loren and others continue to explore, debate
and seek new clues.
LOREN: Archaeology works by making discoveries.
In time, my bet is on that these discoveries are going to be made
up and down the Pacific coast of the Americas.
JIM: This is more anatomical position here.
NARRATOR: When Naia dies, 13,000 years ago,
early humans are arriving in North America
via the ice-free corridor,
and the place she is found in the Yucatán
is only a few miles
from the Ice Age coastline.
So, which route do Naia's people take?
Jim hopes to find clues in Naia's remains.
JIM: Here we're looking at a micro-CT scan.
You see one little stress line right there.
See that little line right along,
right near the junction with the dentine?
NARRATOR: He's looking for telltale signs of stress
from her lifestyle and environment.
JIM: The other place we look is in the long bones
and how they grow.
Here we're looking at Naia's thigh bone,
which is the longest bone
and therefore the one that's gonna give us the most detail.
See these lines?
These are the places where growth has been interrupted,
and then begun again.
One, two, three, four, five, six.
Two, three, four, five, six years we can see.
And the spacing of those lines in Naia
suggests that she had a protein deficiency
during one season of every year.
DOMINIQUE: And so she lived a kind of feast-and-famine life.
¶ ¶
JIM: Seeing that Naia had protein deficiency
during some times of the year
raises the question of why was she protein deficient
if she lived so close to the sea?
DOMINIQUE: There's fish, there are crustaceans.
The sea is a plentiful place.
JIM: Nothing we're seeing in the evidence for her diet
is consistent with being marine-adapted.
It is quite consistent with being strictly terrestrial.
Her people were not adapted to the coast.
DOMINIQUE: Really what it suggests is that she was among
these highly mobile hunter-gatherers
who were heavily reliant on a successful hunt,
their ability to hunt and to kill and to consume megafauna.
And the fact that she appears unable to fish
or make use of marine proteins, that really doesn't make sense
if her people had traveled to the Americas
via a coastal highway.
JAMES: The most dangerous thing in science is to be disappointed
when the evidence doesn't support your theory.
So when Naia was found, given her age,
it was like, "Wow! She had to be a coastal person."
Well, that doesn't show up in her bones.
JIM: While she doesn't disprove the coastal migration theory,
she certainly does not support it.
NARRATOR: But that doesn't rule out others coming
via the coastal route at least 2,000 years before her time.
JAMES: It's just the most fascinating puzzle.
I think it's likely that there were multiple migrations,
following different routes, over thousands of years.
NARRATOR: As for Naia, we are still finding out more
about her life and death.
JIM: The hardest ones to work with are the young people.
You think about a life not lived,
but you also think about the impact of the loss
of that individual on their parents, their siblings,
their young spouses.
NARRATOR: Now they want to piece together the clues
to understand what may have happened to Naia
in the Yucatán cave system 13,000 years ago.
¶ ¶
JIM: When we're working with ancient human skeletons,
we're dealing with the ultimate cold cases.
NARRATOR: Jim Chatters' forensic examinations reveal
an injury from which Naia would not have recovered.
JIM: We know from her pelvis,
she struck the front of her pelvis here,
and it broke away the pubic bones on both sides.
These jagged breaks that you see here are green bone fractures.
They're the kind of breaks that fresh bone gets,
not old, dead bone gets.
This was a serious accident.
It is not easy to break your pelvis;
not to shatter it like that.
NARRATOR: To determine what could have caused
Naia's fatal injury,
Dominique Rissolo and Jim attempt to retrace
her footsteps in the 3D replica of the cave.
DOMINIQUE: It's impossible not to wonder
why Naia was in the cave.
Hoyo Negro had a pool of water in the bottom.
Was she there for water?
This would have been the route that she would have walked.
JIM: This is the most likely way she came in.
The closest entrance is about 2,000 feet behind us.
(heavy breathing)
Imagine she is deep in the cave and she's lost her way,
which would be easy in these caverns.
These tunnels, they join and they separate,
and join and separate,
and getting lost would be a very easy thing to do.
(heavy breathing)
You can turn to the left,
and work your way over some boulders.
DOMINIQUE: Was she being pursued by another animal
inside the cave?
She knows there are large, dangerous animals there.
(heavy breathing)
DOMINIQUE: So, kind of climbing over these rocks
so close to the edge.
You know, maybe trying to find a way around the pit?
JIM: Otherwise we can't get her over to where she fell.
(heavy breathing)
Eventually her light's gonna go out,
and she's wandering in the dark.
(heavy breathing)
And suddenly she takes one final step, and the bottom falls away.
Whoa!
From the floor of that tunnel to the surface of the water below
was right about 100 feet.
30 meters.
And if you look straight down the rim...
DOMINIQUE: Yeah, yeah, yeah, yeah, yeah.
JIM: She's right down there. DOMINIQUE: Oh, my goodness!
JIM: So you fall--Okay, now, Joel, just swing straight down.
From where her body was, it looks like she probably
went through the water and smacked the rocks down below it.
I imagine she was knocked unconscious
and didn't know a thing after that.
NARRATOR: What happens next sets in motion
an extraordinary series of events,
which preserved Naia's remains for the next 13,000 years.
DOMINIQUE: And what we see, of course,
is global sea level rise,
and those rising sea levels are pushing the fresh water
that lies under the peninsula up.
And this chamber is flooding,
and it's flooding surprisingly fast.
Over a few thousand years we see a dry cave,
to a completely flooded one.
It's a really rapid and incredible transformation.
JIM: That sealed the cave off.
And it became absolutely isolated
from the rest of the world.
It wasn't until cave divers,
just exploring for the sheer joy of it,
happened upon this huge black hole.
¶ ¶
NARRATOR: For Dominique and the team of scientists
studying her, Naia's story is not yet complete.
JIM: She comes to us forward in time as a messenger,
and tells us of the life of people lost so long ago.
DOMINIQUE: We know very little about her culture.
We certainly don't know what language she spoke.
We don't have stone tools, we don't have artifacts.
Those have yet to be discovered.
LOREN: One of these days I hope that we actually find artifacts
that are of very clear human origin.
I hope that we find information
about the foods that they're eating.
We may even get as lucky as to find something
that reflects the personal life of somebody.
To me, it's only a matter of time.
Captioned by Side Door Media Services