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Underwater caves, described as the entryway to the underworld.

Gigantic creatures found deep beneath the thick ice of Antarctica.

And a man-made lake where swimmers disappear without a trace.

Twisting rivers, ominous lakes, and seemingly

bottomless oceans.

For centuries, many cultures have...

wondered what lies beneath Earth's aquatic surface.

And with the advances in technology, scientists have delved even deeper into

the world's most mysterious waters, searching for answers.

From lost cities and strange creatures to dark and deadly anomalies,

what secrets are hidden in our planet's vast underwater world?

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

The Pacific Ocean, June 19, 2020.

Billionaire and underwater explorer Victor Vescovo boards an advanced deep

-sea submersible known as the limiting factor, and descends underwater.

His mission is to explore the Challenger Deep, an underwater valley that is the

deepest point on the planet.

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 creep

and creep and creep.

And you get to the bottom, and then you check in with the surface, tell them

that you're okay.

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, oh my gosh, we actually did it.

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 200 747

stacked on top of you.

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.

To get to these locations.

It's an extraordinary undertaking that 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 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.

The most important thing I think I try to get people to realize is that the

ocean is big. I mean really big.

Bigger than you can put your head around.

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.

The deep sea remains the last great frontier 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.

The allure of the deep sea is that it holds something 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.

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.

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.

The understanding of the seas and oceans over time 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.

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.

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 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 a 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,

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 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 see what was there.

In the 20th century, the development of undersea submersibles ushered in a new

era of unprecedented underwater exploration.

The evolution of a deep ocean submersible started in 1930 when a

bathysphere was created where man was put inside of 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 Picard to the bottom of the Challenger Deep for the first time ever.

Today, underwater archaeologists and explorers are using the latest

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

And many experts believe that they are on the cusp of making dramatic new

discoveries on the seafloor.

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.

And also, there's a huge project underway called the 2030 Seafloor

Initiative, where a bunch of different scientists and people like myself, we're

trying to help map the seafloor.

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.

Technology is always the key. 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 thrilling to think that Earth's deep oceans are a future frontier.

But what lies below the sea's surface is not the only underwater environment that

captivates the imagination.

Because there's a network of water-filled caves in Central America

that some believe are an entrance to the afterworld.

The Yucatan Peninsula, Mexico, 66 million years ago.

A six-mile-wide space rock smashes into Earth and sends

billions of tons of rock and debris into the atmosphere, generating tsunamis that

are a half a mile high.

This apocalyptic impact kills 75% of all life on the planet.

and creates about 6,000 sinkholes and underwater cave systems known as

cenotes.

Cenotes are one of the principal sources of water in the Yucatan. So all of the

movement of water in the Yucatan, practically all the movement of water in

the Yucatan occurs in the subsurface.

A cenote is literally a hole in the ground, and it's usually flooded at the

bottom.

The ancient Mayans used the cenotes on the Yucatan Peninsula for a water

supply.

And the cenotes also have cultural significance because of the role that

they played in Mayan religion and Mayan agriculture.

Cenotes were sacred to the ancient Mayan civilization who existed in the region

for about 3,500 years, starting around 2,000 B.C.

These natural wells of fresh water were essential for growing crops in clean

drinking water.

In fact, one of the Mayans' most important cities on the Yucatan

Peninsula was called Mayapan, and it was purposely constructed around these vital

water sources.

Mayapan was a really sprawling, beautiful city built entirely inside a

protective wall.

And within that wall that surrounds it, there are a number of cenotes,

which, of course, if you're an ancient civilization looking for a fresh water

supply, this would have been a phenomenal place to build your walled

city and make sure that you contain all of those bodies of water.

But what's really interesting is that there is one cenote that is outside the

city walls.

And this...

Particular cenote is known as Sacwayum, and it's not incidentally outside the

city walls. The city walls actually zigzag in this really awkward way around

this one pool of water.

Why would the ancient Mayans go through all the effort to build around this one

cenote known as Sacwayum?

Perhaps answers can be found with strange tales.

that modern-day descendants of the Maya still tell to this day.

We've investigated dozens of cenotes across the site. There's several dozen

within the city walls of Maya Pond.

But we began to hear stories about, you know, this cenote that was outside of

the city wall that seemed to be kind of deliberately excluded.

There's several kind of stories I was hearing about Sacwayum.

It's guarded by this important and powerful being.

that it was protected by a feathered serpent, that people had seen the

feathered serpent up in the trees and watched it kind of fly up in the air and

dive down into the cenote when they approached.

In 2013, anthropologist Bradley Russell and his team prepared to learn more

about this storied cenote and its hidden secrets and descended into

Saquayam.

It's about four stories down to water.

So we knew we were going to have to rappel in, get in the water, dive.

And we noticed that there was a small opening.

It was a tunnel that would lead us to something.

So, you know, you went from this large open chamber into this narrow tube, and

then you pass through that, and it opens up into this massive, beautiful, white

-walled, gorgeous second chamber.

It's filled with water the whole way to the ceiling.

We began to explore that. We realized pretty quickly that there were human

remains in the second chamber, including several skulls that are sitting just

completely face up, staring right at you.

It was unusual because there was no logical way that you could have put a

body in there.

We didn't really understand at first how there could be human remains in there.

It turns out that the first chamber sits a little bit above a section of the

lower chamber. And what seems to have happened was that the floor of the first

chamber caved in, brought down stone in kind of a slope, and then human remains

that are lighter than the rock settled out.

When we analyzed samples of the human remains back in the lab, We do a count

that we call the minimum number of individuals, the MNI.

And the MNI we came away with was like 19.

So we know that there's close to a couple of dozen individuals that are

there. And when we did radiocarbon dating on their bones that we had across

that collection, they fell consistently about 1350 AD.

We found that it was mixed age and mixed sex. So every member of society

essentially was represented relatively equally.

The Mayans considered cenotes as the entryway to a place they called Jibalba,

which was really their form of the underworld or hell.

So cenotes were sacred places where, sure, there were accidental drownings,

but there were also intentional sacrifice rituals, potentially to seek

their gods to send water in a time of drought.

It's disturbing to consider what may have happened to Saqwayum to appease the

ancient gods.

But for now, the mystery surrounding this underwater, underground world

endures. We didn't find any evidence for decapitation or things that might

be the violence of the actual sacrificial act.

So we were needing another explanation.

And what we've concluded is that...

There was probably a series of disease outbreaks around 1350 A.D.,

and somebody needed to deal with the bodies quickly, en masse.

And people chose cenotes aquaeum to put the bodies into.

So the mystery of why they're there is slowly being clarified, but

I would never say at this point that we're 100% certain that that's what it

is.

Northwestern Cameroon, August 21st, 1986.

The sun rises over the hills surrounding an ancient body of water known as Lake

Nyos and reveals an apocalyptic scene.

In nearby villages, lifeless bodies are strewn about as if a mysterious force

had swept across the land, killing nearly everything in its path.

There was a terrifying geological catastrophe that occurred.

Something disrupted this lake.

Locals reported a rumbling sound and what might be described as an explosion

as the lake suddenly came to life and anyone who was caught in its

path instantly dropped dead.

The death toll was staggering.

It's estimated around 1,700 people and 3,500 animals were killed across a 14

-mile radius.

With no obvious cause of death, an international team of scientists,

including American biologist George Kling, was dispatched to investigate.

We really didn't know what had happened, what had caused this. And the lake

itself was...

very reddish orange, like a rust color that we really

don't see very often in lakes.

And there was a lot of damage around the shoreline from some large wave that

must have been produced with enough force to wash away all the vegetation

and soil down to bare rock.

And lakes just don't explode like that.

What exploded out of Lake Nyos?

killing everything in its path.

Given that the lake was formed in an ancient volcanic crater, investigators

feared that an eruption deep underground released a surge of deadly gas.

Many of the survivors reported smelling rotten eggs or gunpowder. That's an

unmistakable smell of sulfur.

And they reported feeling warm.

And we know volcanoes produce a lot of sulfur gas and a lot of heat.

But when we started analyzing our samples, we found no sulfur in the lake

water. We found no excess sulfur in the plants around the lake that had been

exposed to this gas cloud.

And when the Army pathologists did autopsies, they found no evidence that

people were poisoned by sulfur gas.

No poisoning by sulfur gas?

Experts were left wondering if the cause of this deadly disaster was even

geological at all.

Local rumors swirled about chemical spills, weapon tests, even

stories about vengeful spirits in the lake.

But George Kling found something intriguing buried in old medical

reports.

a clue pointing to a rather unlikely culprit, a gas that we all produce when

we exhale, carbon dioxide, otherwise known as CO2.

We ran across some older medical literature that had used high

concentrations of CO2 to test for oxygen stress in fighter pilots.

And it turns out that CO2 above concentrations of about 6% acts as a

sensory hallucinogen. And one of the most common reports from the fighter

pilots was that they smelled rotten eggs and gunpowder and that they felt very

warm. So we knew that this was a CO2 release, and we

suspected that the gas was held in the lake.

It turns out that the lake itself could hold a huge amount of gas in the bottom

waters.

Kling's tests reveal that Lake Nyos was primed for disaster.

Over centuries, the lake had become a pressurized chamber of carbon dioxide.

And when that chamber exploded, it released a massive wave of suffocating

gas that raced across the land at over 60 miles per hour.

Lake Neos, as it turns out, was supercharged in carbon dioxide, much

like a soda can if you shook it up before you opened it.

So anyone unfortunate to be caught in its path couldn't breathe.

One of the things that made this event so deadly was that this CO2 gas cloud

was enormous.

first off, but because it was heavier than air, it flowed out of the lake and

down the river valleys very quickly. So even if people had seen the cloud

coming, they couldn't have gotten out of the way. And people just essentially

died in place.

Lake Neos was vulnerable to this kind of an event because it was formed by

volcanic activity, and it's also very deep, so those deep waters could store a

lot of gas.

But once we have the gas build up, we have to have a trigger, and this could

be any number of things.

For example, it could be a landslide that caused the gas burst.

But we'll probably never know for sure what triggered this disaster.

Based on Clinton's discovery, Lake Nyos is now monitored around the clock to

help anticipate another deadly gas event.

But solving the Lake Nyos disaster reveals a far more terrifying question.

With more lakes potentially primed for the same kind of catastrophe,

When and where could this happen again?

Lake Kivu in East Africa is the nasty big brother of Lake Neos.

It's 1,600 times larger. It has 1,000 times more gas in it. And because there

are millions of people living around the shoreline of that lake, it's the largest

ticking time bomb in the world.

There are active volcanoes in the area. And these volcanoes...

could destabilize it and trigger a gas burst?

We haven't looked at every single lake in the world, but we know now enough

about what kinds of lakes could be dangerous.

Knowing that this is a process that the Earth can throw at us, it's natural to

wonder, are other lakes susceptible?

The good news is it doesn't happen everywhere, but the bad news is if

there's one that we don't know about, we need to find it first before it lets us

know. It's there in all the worst ways.

Could such a puzzling catastrophe like the explosion at Lake Nyos happen again?

It's a distinct possibility.

But there's another lake of a very different kind where strange

disappearances leave many asking if the place is cursed.

Hunterdon County, New Jersey.

Nestled beside the sleepy suburbs of Clinton Township lies Round Valley

Reservoir.

First formed in 1960 as a primary water source, this man-made lake is beloved by

locals for its great fishing and scenic views.

But many believe this idyllic watering hole conceals a deadly

secret.

For more than 40 years, people have been disappearing in Round Valley Reservoir,

and not just a few.

More than two dozen men have been lost beneath these placid waters, never to be

seen again.

Locals do believe that this lake is cursed, and it's easy to understand why,

with so many tragic deaths surrounding it in just about 40 years.

And while I can't be sure if it's cursed, there's always one thing that's

given me the chills.

I heard someone say that when one body is found at Round Valley Reservoir,

another quickly replaces it.

We don't even know for sure how many bodies there really are.

When I worked...

In news, I would hear the police scanner crackle to life with Round Valley,

fishermen, trouble, voter, somebody has gone under the water. It's a creepy,

horrible feeling when you hear this because you know that 90% of the time

this is not going to end well.

I can't explain why these people at the bottom of the lake haven't been found.

especially after searching for them with such a degree of intensity.

Even after bringing in cadaver-sniffing dogs, using sonar technology and

submarines to crawl the lake, there was no sign. It's almost as if some of these

people disappeared without a trace.

And an interesting thing, if you're looking for bones in Round Valley, is

that you aren't necessarily going to find a fisherman who disappeared 13

years ago.

you may find a bone that was in the ground long before Round Valley became a

reservoir.

Bones from a time before Round Valley became a reservoir?

There are some who believe that these bones may have been the very reason the

bodies of those who have disappeared here have never been found, and that the

lake's refusal to give up its victims

is actually an act of revenge.

There was a town here once.

For centuries, people put down roots in this valley. It was very fertile and

rich farmland. There were thousands of acres.

And people grew their own food, they raised their animals.

Then in the 1950s, there was a drought in New Jersey.

And they needed a source of water for predominantly Newark, but the

surrounding area as well.

And so they had to fill in somewhere, and Round Valley, they believed, was the

best choice.

People were opposed to the reservoir being built. It was a small farming

community, very close-knit, and no one wanted to leave their homes.

Most of the homes were eventually razed or moved.

Their homes were either torn down or they were put on flatbeds and taken out

of the valley. And that construction started on the reservoir.

In the 1960s, they started filling it.

There was a lot of bad feeling here when the landowners were pushed out of their

valley.

Did these ill feelings carry over? There are people who will say, yes, they did.

There are people who come here who think the town is still here. They still think

they see that church steeple and that barn silo underneath the water.

Are they seeing it?

Not really.

They were torn down, but the foundations were left in place. Of course, there

were fence posts.

There were some things left below.

When you're at Round Valley, you feel the spirit of the people who came before

you.

There is a presence here that can make you feel a little disconcerting.

Some local people call Round Valley the Bermuda Triangle of New Jersey

because as much as this is a place of great beauty and...

great enjoyment it's also a place where death happens

really more than it should the idea that any body of water let

alone a man-made one less than a century old could somehow be imbued with a

deadly curse seems far-fetched to say the least and yet outlandish and

presumably irrational notions such as these have been held by nearly Every

culture throughout history.

But why?

A curse has to be believed in order for it to have power. It's kind of like

hypnosis. You have to be willing to go under hypnosis in order for it to

actually be effective.

So maybe these curses are created by us, by our imagination, by us trying to deal

with the mystery of nature.

It's just a game that we're playing, but we ascribe meaning to it.

So if we ascribe meaning to a curse, could that actually make the curse real?

Although it may be human nature to blame inexplicable tragedies on some sort of

dark force, according to skeptics, there's nothing supernatural about the

disappearances at Round Valley Reservoir.

They claim that these strange occurrences must have a perfectly

rational explanation.

Some people who live around here think it's more a matter of respecting your

environment. And when the wind swirls, you can get waves up to three feet tall

on this reservoir.

And that's where people get in trouble. They're not expecting it.

In my career, I've handled anything from plane crashes, homicides, suicides, you

know, lost children.

But when you're out there in a small boat and there's fog coming across the

lake, it can be very eerie at times.

You have these 40-mile-per-hour winds that come up out of no place.

They only allow small boats.

You have excessively cold water, which leads to hypothermia.

I can guarantee probably 9 out of 10 people that are out on this lake don't

wear their life preservers. I think it's because of those factors.

And you know what? Just plain bad luck.

Period.

So where did the bodies of the lost men of Round Valley Reservoir go?

Could it be that they're merely trapped somewhere deep beneath the lake's

surface, in a place searchers haven't yet looked?

Or are they really victims of a deadly curse?

Vostok Station, Antarctica, February 5th, 2012.

After 20 years of drilling, scientists make a remarkable discovery.

Locked deep beneath the ice for what some estimate to be 20 million years,

scientists reach an extraordinary body of water known as Lake Vostok.

Lake Vostok is the largest subglacial lake in Antarctica and sits about 13,000

feet below the surface of the ice sheet above.

A subglacial lake is one that's formed underneath ice.

Subglacial lakes are a real mystery.

We've only explored a handful of them.

And it's very difficult to explore these hidden environments.

They represent a natural laboratory.

What happens to life if you cut it off from the rest of the world for millions

of years?

When they pulled up water from Lake Vostok, they found microbes in there

that had evolved completely independently from nearly all other life

on Earth.

Lake Vostok is so remote, so isolated from the rest of the planet.

If life could evolve here, it could evolve nearly anywhere.

It was the closest thing we've ever found to life on another planet.

While Lake Vostok is a tremendous discovery, it is just one of many

pristine places in Antarctica where scientists have found not just microbial

life forms, but creatures of all sizes that have never been seen before.

One of the amazing things about working in Antarctica as a marine biologist is

we get to discover new species.

If we go to unexplored areas or places that are much deeper, 80 or 90% of the

species we pull up from the sea are new to science.

And that includes some really strange-looking organisms.

We have the strawberry feather star.

Its central part of its body resembles a strawberry.

I even have two species of sea cucumber named after me because they were

starting to run out of things to name the new species we'd found.

And so it's not a question of will we find new species, it's a question of how

many new species will we find every time we go.

Every time we look at a new pocket of seawater underneath the ice in

Antarctica, we find something we'd never seen before.

Just a few years ago, they found sea spider crabs that have legs up to 20

feet.

They found two-foot-wide sea stars.

They found jellyfish with 12-foot-long tentacles.

Many of these reach sizes that are incomparable to anywhere else on Earth.

The cold, undisturbed waters around Antarctica make an excellent breeding

ground for massive creatures.

Blue whales, the largest animals to ever live on our planet, roam these waters.

And even the mysterious and elusive colossal squid can be found here.

Colossal squid are enormous creatures that are at least 33 feet long, and they

have the largest eyeballs of any creature on the planet.

We've only seen a few of these organisms in real life, but it opens so many

questions about how large animals can be found in some of the most inhospitable

parts of Antarctica.

The Argentina Antarctic Institute completes their excavation of one of the

most extraordinary and massive fossils ever discovered.

It is the skeleton of a sea creature that swam in Antarctic waters 66 million

years ago called Elasmosaurus.

Elasmosaurus was a real sea monster swimming around the Antarctic.

It's the heaviest marine reptile fossil that's been found around Antarctica.

It was up to 40 feet long and possibly 15 tons worth of animal.

It was thought to have lived right up to the extinction event that killed the

dinosaurs. But it was the largest swimming reptile in the oceans around

Antarctica. When the story hit the news, people started saying, Doesn't this

resemble the Loch Ness Monster?

Doesn't this resemble other sea monsters and lake monsters around the world?

Begging the question of whether creatures like the Elasmosaurus still

exist out there in the sea caves of Antarctica to this day.

We know this massive critter lived there, right? So things that you might

call a monster, could they live under those ice shelves? Of course they could.

98% of the ocean bottom underneath these huge ice sheets off of Antarctica are

completely unexplored.

There's absolutely going to be stuff that we've never seen before that

surprises us, and that tells us more about life on our planet.

Perched on the shore of the Arabian Sea sits the modern city of Dwaraka.

It was named after a legendary city 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 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.

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 sea floor, 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, they could be

walls of temples.

The archaeologists are now saying that they are perhaps datable to 9000 BCE.

If it is true, then archaeological fact supports the story.

And that is what makes it more interesting and more significant, this

discovery.

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 Dworka 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.

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.

Will we find remnants of an ancient civilization 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.

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're going to discover in the next 50 years.

It's fascinating to know that a land once considered the stuff of legends is

actually real.

Hidden for centuries like an underwater time capsule, the mysteries lying

beneath the surface of our watery planet are countless.

From lost ancient cities to undiscovered worlds filled with strange

and exotic creatures.

What will further underwater exploration reveal about Earth's oceans and our

ability to survive in the deep dark sea?

The possibilities are as vast as the water itself and for now

remain unexplained.