Original subtitles

WILLIAM SHATNER: Massive structures

lost beneath the waves for thousands of years.

Sunken continents

that were home to advanced civilizations...

...and a remote mountain lake filled with gold treasure.

For as long as man has roamed the Earth,

we've also explored the world's oceans

in order to find out what lies below.

Is the planet's vast underwater world hiding profound secrets

in the silent expanse of cold and darkness?

What can the depths of the sea tell us about our human nature

and perhaps a lost human history?

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

♪ ♪

Billionaire and underwater explorer Victor Vescovo

boards an advanced deep-sea submersible

known as the Limiting Factor

known as the Limiting Factor and descends underwater.

and descends underwater.

His mission is to explore the Challenger Deep,

an underwater valley that is the deepest point on the planet.

VICTOR VESCOVO: I was the fourth person to dive

to the bottom of Challenger Deep.

Within the first thousand meters,

it goes from being brilliant sunshine in the Pacific

to pretty much fully black.

So you descend in the water column, as we call it,

for up to four hours,

steadily going down, watching that depthometer creeping,

steadily going down, watching that depthometer creeping, creeping, creeping.

creeping, creeping.

creeping, creeping. And you get to the bottom and then you

And you get to the bottom and then you

check in with the surface, tell them that you're ok.

(cheering)

At that point, it takes seven seconds for the transmission

to actually get to the surface

and seven seconds for it to go down.

It's such an incredible feeling of relief

and a sense of incredible achievement that,

and a sense of incredible achievement that, "Oh, my gosh, we actually did it."

"Oh, my gosh, we actually did it."

JOSH YOUNG: Challenger Deep

is the most deep, dark and dangerous place on the planet.

When you get to the bottom, the pressure is

the equivalent of having

the equivalent of having 200 747s stacked on top of you.

200 747s stacked on top of you.

200 747s stacked on top of you. Unimaginable crush pressure there.

Unimaginable crush pressure there.

You need a properly engineered submersible

that can go down, withstand the pressure,

stay down there,

and continue to explore these depths.

MONTY HALLS: To get to these locations,

it's an extraordinary undertaking

it's an extraordinary undertaking and it should be celebrated.

and it should be celebrated.

They are incredibly difficult to get to,

they're extremely dangerous, they're very hostile to people.

We don't belong down there.

SHATNER: The ocean is a vast expanse

that is almost unimaginable in scope.

And although humans have been traveling

across the high seas for thousands of years,

we still only know a fraction of what lies

beneath the waves.

VESCOVO: The most important thing I think

I try to get people to realize is that the ocean is big.

I try to get people to realize is that the ocean is big. I mean, really big.

I mean, really big.

Bigger than you can put your head around.

Bigger than you can put your head around. It is 70% of planet Earth.

It is 70% of planet Earth.

And it's three-dimensional.

It's not a two-dimensional surface like the land is.

And so, 80% of it is still completely

unmapped and unexplored.

HALLS: The deep sea

remains the last great frontier

remains the last great frontier for us as a species.

for us as a species.

We know way more about the surface of the Moon,

way more about the surface of the other planets

than we do the deepest spots

in the ocean.

It's a mystery we've just started to unravel.

YOUNG: The allure of the deep sea is that it holds something

YOUNG: The allure of the deep sea is that it holds something in everyone's imagination.

in everyone's imagination.

Not fully knowing what is there

enables everyone to come up with their own vision

of what might be there.

What creatures might live down there?

Might there be sunken ships and gold,

and where might that be?

That is what sparks the curiosity

that we need to keep exploring

and to keep investigating what's down there,

what's out there.

SHATNER: The recent dives to the bottom of the ocean

have shed new light into the darkness of its depths.

But these voyages are just the latest chapter in mankind's

long quest to uncover what secrets are held in the seas.

In fact, our fascination with the ocean

goes back thousands of years.

LYNNE McNEILL: Throughout history

and cross-culturally as well,

we see a really consistent pattern of belief

that under the water is an entirely other world...

...full of creatures

like a Kraken or a Leviathan.

And it's not just oceans.

Lakes are always populated with these monstrous creatures,

like the Loch Ness Monster.

The message we get

is that no body of water is safe.

MICHAEL TUTTLE: The understandings of the seas and oceans over time

MICHAEL TUTTLE: The understandings of the seas and oceans over time has changed dramatically.

has changed dramatically.

The ocean was basically seen

by seafaring people, like the ancient Greeks were

or ancient Phoenicians were...

...as the big, bad black sea.

They didn't have the ships

to go against the currents and the winds.

And if you sailed far enough, you'd die.

ROBERT SCHOCH: For so long, no one really knew

what the extent of the oceans were, what's under them.

Even in the time of Columbus, late 15th century,

people were worried,

some people thought the Earth was flat,

that you could literally get to the end of the ocean

and fall off the edge.

SHATNER: Humanity has always been humbled by the vast power of the ocean.

But during the scientific revolution in the 16th century,

we started to get a better understanding

we started to get a better understanding of the underwater world.

of the underwater world.

In 1521, Portuguese explorer Ferdinand Magellan

attempted to measure the depth of the ocean by attaching a line

to a cannonball and tossing it over the side of his ship.

After lowering the cannonball 2,400 feet,

Magellan declared that the ocean was immeasurably deep.

Magellan went out and tried to measure the depth of the oceans.

He wasn't largely successful with that,

but it sort of opened the door that,

but it sort of opened the door that, wow, this is really deep

wow, this is really deep

and we need to do more exploration.

That was furthered later

with the HMS Challenger expedition in the 1870s

that went all the way around the world

that went all the way around the world to explore the deep oceans.

to explore the deep oceans.

And the most significant thing it found was the deepest part,

which is the Challenger Deep,

which was named after the expedition.

Over time there became more of a curiosity to the oceans.

To want to go down and to be able to go down to,

to see what was there.

SHATNER: In the 20th century,

the development of undersea submersibles

ushered in a new era

of unprecedented underwater exploration.

YOUNG: The evolution of a deep ocean submersible started

in 1930 when a bathysphere was created,

where a man was put inside of a, essentially, a vessel...

...and dipped down into the ocean held by a tether.

That was furthered later

by the bathyscaphe in 1960,

the Trieste, which took Don Walsh and Jacques Piccard

to the bottom of the Challenger Deep

for the first time ever.

SHATNER: Today, underwater archaeologists and explorers

are using the latest submersible technology

to try to unravel the mysteries that lie

to try to unravel the mysteries that lie within the ocean.

within the ocean.

And many experts believe

that they are on the cusp of making dramatic

new discoveries on the seafloor.

VESCOVO: My hopes for ocean exploration in the near term

is to bring the very deep places,

the very dangerous places to a point of accessibility

where we can take any scientists down to them

to explore them.

Also, there's a huge project underway

Also, there's a huge project underway called the 2030 Seafloor Initiative,

called the 2030 Seafloor Initiative,

where a bunch of different scientists

where a bunch of different scientists and people like myself,

and people like myself,

we're trying to help map the seafloor.

SHATNER: The Seabed 2030 Initiative

is gathering information collected all over the world

by science vessels,

merchant ships, and underwater drones.

Their goal is to map the entire ocean floor

by the year 2030, a feat that seemed impossible

for most of human history.

VESCOVO: Technology is always the key.

VESCOVO: Technology is always the key. Technology allows us

Technology allows us

to do things that we couldn't do before

and see those things that no one has ever seen before.

It's human progress

and really pushing ourselves to the next level.

It's really quite extraordinary that we have the ability

to journey to the very bottom of the ocean,

and scientists are making

incredible underwater discoveries all the time.

For instance, a new landmass was recently found

For instance, a new landmass was recently found off the coast of New Zealand.

off the coast of New Zealand.

And there are those who believe that it could be

And there are those who believe that it could be part of a lost continent.

part of a lost continent.

SHATNER: A team of geologists at GNS Science

announce a major discovery

related to the Earth's continents,

the vast landmasses that make up the planet's surface.

The scientists found that,

in addition to the seven continents

that humans have known about for centuries,

that humans have known about for centuries, there's also an eighth continent

there's also an eighth continent

located directly underneath New Zealand,

which they named Zealandia.

Zealandia sank into the ocean

approximately 50 million years ago,

and its existence suggests

that there may be even more lost continents

that were swallowed up by the sea.

The Earth has cycles of sea level rise and sea level fall.

Over the last hundreds of millions of years,

as climate has warmed we get sea level rise;

cold periods, sea level fall.

There's a huge amount of land which is now

There's a huge amount of land which is now covered by the sea.

covered by the sea.

covered by the sea. MICHIO KAKU: 10,000 years ago,

MICHIO KAKU: 10,000 years ago,

with the end of the Ice Age,

sea levels were dramatically lower than they are now.

And because of the melting

of the ice, sea levels have risen since then,

and cities that may have existed thousands of years ago

could be lost in history as a consequence.

SHATNER: For thousands of years, cultures from around the world

have told stories about long-lost continents

that were home to human civilizations

and are now submerged beneath the waves.

Perhaps the most famous is the legend of Atlantis,

a massive island that was home to an advanced civilization

before it supposedly sank into the ocean after an earthquake.

HUGH NEWMAN: There's been more books written about Atlantis

than any other lost continent in history.

There are many

sunken cities, lost lands,

destroyed continents all around the planet

destroyed continents all around the planet in legend and history.

in legend and history.

For example, we have the lost land of Hy-Brasil,

which was thought to be

200 miles off the coast of Ireland,

and it was even on maps until the 1800s.

SHATNER: One of the most intriguing lost continents is a landmass

that is believed to have once existed in the Pacific Ocean.

A mythical land that is known as Mu.

The first person to write extensively

about the lost continent of Mu

was a Scottish writer

by the name of James Churchward.

In the 19th century, he was in India when he visited

a monastery.

And the monks there had records, apparently, tablets

that referred to this place called Mu

that was this huge continent that supposedly existed

from Hawaii in the north

down to Easter Island in the southeast,

right the way across to Micronesia in the west.

And the people there were supposedly called the Naacal.

The continent of Mu thrived perhaps 50,000 years ago

and was sunk beneath the waves,

possibly at the end of the last Ice Age.

My great-grandfather James Churchward,

eventually he became friends with the rishi of the temple

that he visited in India.

And the rishi mentioned that he was a member

And the rishi mentioned that he was a member of the Naacal brotherhood,

of the Naacal brotherhood,

the holders of wisdom and knowledge

of the lost continent of Mu.

They were mighty navigators and sailors

and established civilization in other parts of the world.

SHATNER: According to James Churchward,

SHATNER: According to James Churchward, the Naacal civilization had a population

the Naacal civilization had a population

of more than 60 million people at its peak

before a massive volcanic cataclysm caused Mu to vanish

before a massive volcanic cataclysm caused Mu to vanish beneath the waters.

beneath the waters.

So far, no evidence of the lost continent

has been found on the ocean floor.

But some researchers claim that, incredibly,

a tiny remnant of Mu may still exist above water today

on an island located in a remote part of the Pacific Ocean.

Roughly 2,500 miles northeast of Australia

lie the ruins of a once great ancient city.

Nan Madol.

Nan Madol is a complex of man-made islands

built with massive stone blocks that float atop

built with massive stone blocks that float atop a submerged coral reef.

a submerged coral reef.

COLLINS: So as you approach Nan Madol,

there are a series of islands,

and they're built actually on coral,

the only place in the world where this actually occurs.

And you've got all these incredible structures

made of these prismatic blocks.

NEWMAN: At Nan Madol, you have these

ridiculous basalt columns, they're huge,

some of them up to, like, 40 tons,

some of them up to, like, 40 tons, even more in some cases.

even more in some cases.

Some of them are raised very high up in the air,

on the very top levels.

So there's a real problem when it comes to try and understand

how they moved these millions of tons of basalt columns.

COLLINS: One of the biggest mysteries

surrounding Nan Madol

is that nobody really knows who constructed it.

But there's some very strange stories

about how the city came into existence.

For instance, one of the stories talks about

it being constructed by so-called master builders...

...turning up and using a magical force...

...to raise the blocks into the air and put them into place,

almost as if they could levitate these blocks.

SCHOCH: Some people actually suggested

that maybe Nan Madol was the last remnant of Mu

that was still above water...

...and it was simply

...and it was simply indicative of what had sunk

indicative of what had sunk

beneath the waves from this advanced civilization.

Nan Madol is in Micronesia,

so it fit the correct general area.

And this is one reason people thought in terms of Mu.

NEWMAN: When it comes to looking for this lost continent of Mu,

places like Nan Madol really do suggest

there could be much more down there than we realize

on the bottom of the ocean.

It's hard to picture an entire continent,

with people living on it, simply vanishing into the sea.

with people living on it, simply vanishing into the sea. And yet...

And yet...

...all over the world, there are legends of lost

civilizations that were swallowed up by the oceans.

But could such legends actually be true?

Perhaps the answer can be found by examining

a mysterious structure located in the Pacific Ocean

a mysterious structure located in the Pacific Ocean that has come to be known as

that has come to be known as

Japan's Atlantis.

SHATNER: At the western end of the Pacific Ocean,

67 miles off the coast of Taiwan,

is the Japanese island of Yonaguni.

It is one of some 6,800 landforms

It is one of some 6,800 landforms in the Japanese archipelago,

in the Japanese archipelago,

in the Japanese archipelago, a chain of small islands

a chain of small islands

located near the southern tip of Japan.

But just off the coast of Yonaguni lies

a mysterious complex of underwater stone formations

known as the Yonaguni Monument.

SCHOCH: It's an absolutely incredible structure,

and it looks like a giant staircase.

Steps in the bedrock with terraces.

The symmetry and the regularity that people see on it

just makes a astounding impression.

NEWMAN: It looks like a huge, multifaceted pyramid platform

that stretches over a huge area

with all these details carved into it.

There's areas where monoliths were said to have been standing.

There's even dolmens or large slabs like lintels

covering areas and creating doorways and other features.

HALLS: When you look at some of the rock structures,

it looks undeniably man-made.

But with that comes a whole series of questions.

How did it get here? How long has it been here?

What is the structure you're looking at?

SHATNER: The Yonaguni Monument was discovered by divers in 1987,

SHATNER: The Yonaguni Monument was discovered by divers in 1987, and since that time,

and since that time,

experts have debated whether it's a natural formation

caused by erosion or an artificial structure

that was carved by man in the distant past.

Researchers who believe that the monument is man-made

Researchers who believe that the monument is man-made claim that it is the ruins

claim that it is the ruins

of a massive stepped pyramid complex

that is nearly 500 feet long, 130 feet wide, and 90 feet tall.

The Yonaguni Monument was originally above water,

but at some point in the past,

but at some point in the past, waters rose up and covered it

waters rose up and covered it

and it's now beneath almost 100 feet of water.

You have not only these geometrical structures,

these terraces,

but also some strange monuments,

including what appears to be this human head.

It's 23 feet tall

and it has these hollow sunken eyes.

It almost looks like the moai statues of Easter Island.

It looks hauntingly like

some kind of giant of the past.

SHATNER: Underwater archaeologists who have visited Yonaguni

have also noted that there appears to be

a sculpture of a sea turtle.

And some even claim there is a carved roadway

circling the entire site.

NEWMAN: There's so many elements to it

which suggest it's at least been manipulated by man,

because it looks like it's been carved from solid rock.

And one of the theories that has kind of caught

many researchers' attention is that it could be evidence

of a lost civilization many thousands of years old.

SCHOCH: Some people have thought of Yonaguni

being "Japan's Atlantis,"

in the sense that if Yonaguni is an artificial,

human construction from very ancient times,

it must represent the tip of the proverbial iceberg

of an advanced civilization

thousands of years ago that somehow disappeared

into the ocean under the waves.

SHATNER: Is the Yonaguni Monument

SHATNER: Is the Yonaguni Monument the remains of a lost civilization?

the remains of a lost civilization?

And if so, how long ago did that civilization exist?

HALLS: One of the really, really interesting,

mystifying things about the Yonaguni Monument

is the depth of water.

is the depth of water. So, it's 25 meters.

So, it's 25 meters.

Now, if we were relying on the pulses of sea level rise

from kind of the end of the Ice Age

10,000 years ago, that means that the Yonaguni Monument

would be 12,000 to 14,000 years old.

That's going to predate

the earliest civilizations we know of by 7,000 years or so.

If the Yonaguni Monument was man-made, then it is a truly

seismic discovery in terms

of the history of our species because,

potentially, the cradle of human civilization was Japan,

potentially, the cradle of human civilization was Japan, was off the coast of Japan.

was off the coast of Japan.

SHATNER: Is it possible that the Yonaguni Monument

is not only man-made

but also much older than any other ruin

but also much older than any other ruin that's ever been discovered?

that's ever been discovered?

that's ever been discovered? Many scientists believe

Many scientists believe

that further research on this remarkable structure

could rewrite history

and offer tangible evidence in support of the theory

and offer tangible evidence in support of the theory that there are remnants of lost

that there are remnants of lost

civilizations hidden in the world's oceans.

TUTTLE: Are there some foundational cities

underneath the water?

I wouldn't bet against it.

If we want to unlock the secrets of ancient civilizations,

we may very well have to look underwater.

HALLS: What we are beginning to learn

is the huge potential of

mysteries in the sea, as in what the sea can give us

in terms of new discoveries, new glimpses into other worlds.

And the Yonaguni Monument is a real manifestation of that.

The mere possibility

that the ruins of an ancient civilization

could be lying on the floor of the Pacific Ocean

is fascinating.

But our next underwater mystery can be found not in the ocean

but at the bottom of a vast lake.

A lake that holds gold and silver artifacts that date back

thousands of years.

SHATNER: High atop this 5,500-mile-long mountain range

lies Lake Titicaca,

one of the most picturesque bodies of water in the world.

Lake Titicaca sits at a remarkable elevation

of 12,500 feet, which is roughly two miles above sea level.

REINHARD: Lake Titicaca is a massive lake

REINHARD: Lake Titicaca is a massive lake in the midst of a mountain range,

in the midst of a mountain range,

and it's about 120 miles long

and 30-some miles wide.

It extends down nearly a thousand feet,

and it's the highest navigable lake in the world.

It's quite unusual to be on something

that looks like a sea when you're on it

and see snowcapped peaks... (laughs) surrounding it.

SHATNER: You might think that a lake located

at such a high and remote location would have no traces

of human activity.

But what's incredible

about Lake Titicaca is that, for decades,

archaeologists have been finding

mysterious gold artifacts submerged

mysterious gold artifacts submerged within its icy waters.

within its icy waters.

FOERSTER: Excavations of Lake Titicaca found

2,000 artifacts of gold, silver, and pottery.

Normally, of course on land you would find that, but to find it

in the lake was very mysterious and surprising.

REINHARD: There's more than 40-some carved stone boxes

that have been found.

Many of them have little grooves in their sides,

which was where the ropes were

tied around them so they wouldn't slip out

when they were being lowered into the water.

Now, the exciting thing about finding these boxes

with a lid is the kinds of finds that were being made in them,

with a lid is the kinds of finds that were being made in them, such as a gold vase,

such as a gold vase,

such as a gold vase, a gold medallion,

a gold medallion,

a gold medallion, and gold feline figurines.

and gold feline figurines.

SHATNER: But why would the ancient peoples of this region make

a difficult trek to this lake that is located atop

one of the least accessible mountain ranges in the world

to leave so many gold artifacts

at the bottom of the lake?

This entire area of the Andes is associated with the Inca.

And they are responsible for many of the finds

that have been made in Lake Titicaca.

The Inca were a South American civilization

that controlled 2,500 miles

stretching all the way from Peru, modern-day Bolivia,

Guatemala into Chile and Argentina.

REINHARD: Lake Titicaca was one of the most sacred places

REINHARD: Lake Titicaca was one of the most sacred places in the entire Inca Empire.

in the entire Inca Empire.

It was sacred because it was

one of the most important freshwater bodies of water

one of the most important freshwater bodies of water in all of South America.

in all of South America.

BELLINGER: When the Inca realized the incredible value

of the Lake Titicaca basin...

...they initiated a program of religious pilgrimages,

essentially, saying that

their key creator god, known as Viracocha,

rose up out of the waters of Lake Titicaca

to create all humanity.

REINHARD: Lake Titicaca

REINHARD: Lake Titicaca is the mythological origin

is the mythological origin

of the entire Inca Empire.

They believed that they were descendants of the cultures

that had evolved at Lake Titicaca.

There were legends of temples and whatnot

underwater in Lake Titicaca, long before the Incas.

SHATNER: According to Inca legend,

a civilization that existed centuries prior to them

rose from the waters of Lake Titicaca.

Remarkably, archaeologists have uncovered evidence

which suggests that there may be some truth to this myth.

In August of 2000, an Italian team of divers

uncovered traces of a paved road,

a stone terrace,

and a wall nearly a half a mile long.

BELLINGER: They found themselves swimming along what looked to be

BELLINGER: They found themselves swimming along what looked to be an ancient paved roadway.

an ancient paved roadway.

And they passed what looked like it could have been

terraced agricultural fields

quite similar to what you can see

around the shores of the lake even today.

But what they found at the end of this road

really astonished them.

It was a giant temple complex,

It was a giant temple complex, the size of two football fields.

the size of two football fields.

Archaeologists were able to see that these were

extremely ancient, 1,000 to 1,500 years old.

REINHARD: We found artifacts

dating from around 300, 400 AD, until about 1100 AD.

And then you have the Inca coming in around 1400 AD.

So that means that Lake Titicaca

was a sacred place to civilizations

that dominated the Andes before the Incas.

SHATNER: The ruins found at the bottom of Lake Titicaca would seem

to validate the Inca belief that there was another culture

present there long before them.

But how did these ruins become submerged?

SCHOCH: We've got these structures underwater.

They're 1,500 years old or older.

It's one thing to find artifacts underwater

and they may have been dropped or may have been

purposefully, um, sacrificed to the lake, if you would.

But when you find temples and walls and roadways underwater,

But when you find temples and walls and roadways underwater, you know that something was going on

you know that something was going on

at a much earlier period.

Certainly they were not building these things underwater.

We do know that Lake Titicaca fluctuates in terms of

the water levels over time over thousands of years.

So this is incredibly important and fascinating

and it ties in with Inca beliefs

that they thought this was a place

that was literally the birthplace

of civilization for them, up in the high Andes.

FOERSTER: The enduring mysteries associated

with Lake Titicaca would be, for example, who was the first

civilization to live here?

We have no idea how far back in time humanity goes

in terms of the first habitation or inhabitation of this lake.

But that's why there should be more underwater archaeology

done here in Lake Titicaca,

in order to be able to fully comprehend the true history

of this amazing aquatic area.

What else might be submerged at the bottom of Lake Titicaca?

Could there be other artifacts

that might change our understanding of human history?

Well, the diving expeditions continue,

as do the revelations.

But let's consider a different kind of undersea discovery.

One that makes us question not our past

but rather whether we're alone in the universe.

SHATNER: 100 miles off the coast of San Diego,

a group of U.S. warships are conducting

routine training exercises

when they detect a number of unidentified

flying objects near Catalina Island.

They were picking up multiple targets on the radar system,

but they had a new system they were testing.

So the theory was that it was just glitches,

and so they rebooted.

But sure enough, these targets showed up again.

And this goes on for a series of some days,

and then they vectored jets to go and investigate.

SHATNER: As Navy F-18 fighter jets approach the area where the UFOs

had been detected on radar,

the pilots see a white, oval-shaped object

that has no wings

and resembles a giant Tic Tac.

But then suddenly,

it rapidly descends 80,000 feet in less than a second

and hovers above the surface of the water.

Naval Officer Ryan Weigelt

was stationed on the nearby USS Princeton

on the day of the encounter.

I was called to the bridge by the CO

I was called to the bridge by the CO and when I got up to the bridge,

and when I got up to the bridge,

the whole office was much more crowded and chaotic than normal.

People were raising their voice

on seeing some of the things that they were seeing.

It was a very excited atmosphere.

I noticed that to my left-hand side

was a video monitor where the FLIR footage

was being fed into the Princeton,

so I could see what the jets were seeing.

On my right-hand side

I am watching them on a radar screen

that gives information on altitude

and speed and heading and...

Seeing what I saw,

it's impossible for anything that we own or have created

to withstand the G forces that would be created

from doing any type of thrusts,

like what this Tic Tac was doing.

Two of the pilots involved in the Tic Tac incident,

Commander David Fravor

and Lieutenant Commander Alex Dietrich,

have stated that under the infamous Tic Tac,

there was an area of water that was roiling,

as if there was this object under the waves.

And this object was about

the size of a Boeing 737.

SHATNER: Navy eyewitnesses

have reported that the Tic Tac was moving

erratically above the surface of the water,

as though it appeared to be interacting

with the unidentified object located beneath the waves.

Moments later, the Tic Tac

made a series of seemingly impossible maneuvers

to evade the Navy jets before accelerating away

to evade the Navy jets before accelerating away at thousands of miles per hour.

at thousands of miles per hour.

And the pilots claim that when they tried to get a second look

at the underwater object, it had somehow vanished.

I am a person who needs to see

to really believe and...

seeing what I saw during that time frame,

I think any rational-minded person would be somewhat alarmed

that there is this technology out there

that is far superior to us.

POPE: That technology isn't something we have.

So, if not us, who or what?

And what we're hearing about now is just the tip of the iceberg.

There have been consistently a lot of reports

of unidentified objects under the ocean.

People have seen them from the shore,

going into the sea and coming out of the sea.

We've all heard of UFOs because they fly in our atmosphere,

but what happens if they can hit the oceans and go underwater?

These are USOs.

These are USOs. Unidentified submerged objects

Unidentified submerged objects

are objects that have the ability to plunge

right into the ocean and disappear.

This is something that we cannot duplicate

with our technology, and so these objects

are of very intense interest because it means

that a new technology is being harnessed by some unknown party.

They could be even, perhaps, extraterrestrial.

SHATNER: Extraterrestrial USOs?

Flying into and out of the world's oceans?

For some, that may sound like something

out of science fiction.

But curiously,

more than a decade after the Tic Tac incident,

the United States Navy continues to detect USOs

off the coast of Southern California.

In July of 2019, Navy aircraft flying in the same area

recorded video which appears to show

an unidentified flying object disappearing into the ocean.

POPE: What's really interesting about this

is that all this is happening

in a fairly small geographical area.

So you've got a series of encounters

happening off the coast of San Diego.

To have all this going on in one very concentrated spot,

one has to say, is this just a coincidence

or is there a connection?

SHATNER: If there are, in fact, extraterrestrial USOs

SHATNER: If there are, in fact, extraterrestrial USOs lurking in this area,

lurking in this area,

then where are they hiding when they go underwater?

Satellite imagery reveals a strange

underwater formation only six miles off the coast.

The three-mile-long anomaly lies 2,000 feet

below the surface of the Pacific Ocean,

and the discovery led many to wonder

if this formation might actually be

an artificial structure.

an artificial structure. POPE: A lot of people

POPE: A lot of people

POPE: A lot of people got very excited by this discovery.

got very excited by this discovery.

It's really quite striking

and it really does look artificial.

It looks like the thing's got this huge flat roof.

It looks like it's got pillars or columns.

It looks like it's got pillars or columns. And it makes you wonder,

And it makes you wonder,

is this the remains of some ancient civilization

that's just hidden by rising sea level?

Or is it, as some believe, an extraterrestrial base?

KAKU: If all these objects are buzzing our aircraft,

they must have a base of operations.

But you see, if they have a base of operations

as easily detected by us humans,

it would sort of defeat the purpose of observing us.

So perhaps there's an underwater base

that is away from prying eyes of humans,

so that we don't interfere with their plans.

That cannot be ruled out.

Is it really possible

there are extraterrestrial spacecraft

lurking in the ocean, as members of the U.S. military claim?

lurking in the ocean, as members of the U.S. military claim? As of now, we can't say for sure.

As of now, we can't say for sure.

But sometimes the ocean's depths reveal evidence

which proves that an incredible story is true.

which proves that an incredible story is true. Like off the coast of India...

Like off the coast of India...

...where archaeologists rediscovered

the ruins of a mythical

underwater city.

SHATNER: Perched on the shore of the Arabian Sea ♪ ♪

sits the modern city of Dwarka.

It was named after a legendary city

It was named after a legendary city that was also called Dwarka.

that was also called Dwarka.

The sacred Hindu text the Mahabharata

explains that the legendary city of Dwarka

was said to be the dwelling place of Lord Krishna

before it sank into the sea following a fantastic

before it sank into the sea following a fantastic battle in the sky between Krishna

battle in the sky between Krishna

and another Hindu god Lord Salva.

For centuries that story was believed to be merely a legend.

That is, until 1983

when underwater ruins were discovered off the coast.

Ruins which suggest that the legendary city of Dwarka

was not a myth but rather a real place.

RICHARD BATES: S.R. Rao

was an archaeologist, a marine archaeologist

working with the Archaeology Institute in India.

And he started the exploration

from the shore of present-day Dwarka.

And on the floor of the ocean,

on the seafloor he found wall structures,

blocks three foot by three foot, probably a foot thick,

stacked as if they were building continuous wall structures.

They could be city walls, they could be street,

building walls, um, they could be walls of temples.

DEEPAK SHIMKHADA: The archaeologists are now saying that they are perhaps

datable to 9000 BCE.

If it is true,

the archaeological fact supports the story.

And that is what makes it more interesting and more

significant, this discovery.

SHATNER: The discovery of sunken ruins off the coast of Dwarka

is proof that underwater exploration can turn some myths

into reality.

Many experts believe that Dwarka is just the tip of the iceberg,

and that there are even more secrets lurking in the deep

that could challenge

our understanding of both our planet...

...and human history.

YOUNG: The biggest unanswered question

regarding the oceans is,

now that we've opened this door to this scientific exploration,

what can be found

that will have some impact on our own lives?

Well, the oceans, they drive weather

and regulate temperature

in ways that we don't fully understand now,

and the only way that we're going to completely understand

is to go down there and to gather more data.

And that's just one example.

The ocean is constantly throwing up surprises.

VESCOVO: Will we find remnants of an ancient civilization

VESCOVO: Will we find remnants of an ancient civilization that no one knew about?

that no one knew about?

I don't know, but that

unknown is what drives me, because there's a chance

that we'll find something revolutionary

at the bottom of the ocean

that no one had ever thought of before.

HALLS: Even though we are the first

generation ever to explore under the sea

with any level of technology and rigor,

the deep sea still eludes us.

And the good thing is,

it's becoming more and more accessible.

Imagine what we can discover in the next 50 years.

So, what do you think?

What still lies in the deepest, darkest corners of the ocean?

Well, in spite of everything we've learned

about the underwater world,

we simply don't know what else is down there

we simply don't know what else is down there waiting to be found.

waiting to be found.

And that mystery is what compels us to keep diving,

to keep searching, in the hope that one day

we will uncover all the secrets of the deep that,

we will uncover all the secrets of the deep that, for the moment, remain...

for the moment, remain...

unexplained.

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