Original subtitles

[narrator] A mysterious mummy dressed in a pinstripe suit

is found on the top of Mexico's highest mountain.

I'm not a conspiracy theory guy, but this seems like a cover up.

I want to know how did this guy in a suit

end up at the top of this mountain?

[narrator] A massive wall built under a remote glacier,

As soon as you enter it, you realize this place is immense.

Was this wall built to keep enemies out

or to keep something in?

[narrator] A US Air Force bomber on a top-secret nuclear mission,

vanishes from the face of the earth.

[Dr. Anthony Cantor] I asked myself,

were they also trying to hide the fact that a plane armed with a nuclear bomb

crashed into the side of a mountain?

Could discoveries like this one reveal

it's more frequent than we thought?

[narrator] These are the strangest mysteries

trapped in the coldest places.

Lost relics,

forgotten treasures,

dark secrets,

locked in their icy tombs for ages.

But now,

as ice melts around the world,

their stories will finally be exposed.

[narrator] Near the top of Mexico's highest mountain,

lies a volcano named Pico De Orizaba.

At over 18,500 ft,

the snow-covered peak can be seen for miles.

[Meagan McGrath] What makes Pico De Orizaba special and interesting,

is it's a relatively short drive from Mexico City.

You drive a few hours and you can find yourself really at the highest

volcano in North America.

[narrator] It may be physically close to civilization,

but it feels a world away.

[Cantor] The top of this mountain,

it is a snowy, baron, harsh environment.

Blizzards are constantly tearing at it and the snow never melts.

[narrator] In 2015,

a group of climbers slowly make their way up the treacherous terrain,

but just a 1000 feet from the summit,

they stop in their tracks.

There's a strange figure protruding from the ice and snow.

As the climbers edge closer,

the figure takes shape,

revealing a gruesome discovery.

It's a corpse.

And not just any corpse,

it's a mummy.

[Cantor] Mummies are fascinating.

What's very intriguing here is,

this was not an intentional mummification.

This body was preserved

by the snow and the ice and the cold.

How did it get there?

What does it have to tell us?

[narrator] For decades, mountaineers have flocked to this volcano,

to conquer its summit.

And many have died trying.

But it's immediately apparent

this man was no climber.

The mummy had no equipment, no proper jacket,

no proper pants, no water, no hat.

So how did he get here?

What was he even doing here?

[narrator] It's not only the lack of gear that's strange,

it's his clothing.

The body is dressed in a pinstripe business suit, and a white dress shirt.

Even stranger,

when they search his clothing,

they find no wallet, no papers, no watch,

there's nothing on his person to identify him.

This seems really suspicious like a...

I'm not a conspiracy theory guy,

but this seems like a cover up kind of situation.

I want to know how did this guy in a suit,

end up at the top of this mountain.

[narrator] Without the proper gear,

it would be impossible to make it this far up the mountain.

So if he didn't come up the mountain

there's only one other way he could have come,

from above.

[narrator] Pico De Orizaba is at the southern end

of Mexico's chain of volcanoes.

Planes crossing the mountain range fly right over the volcano.

Was the man on board on one of these flights?

Could he have parachuted from a passing plane

and landed on the side of the volcano?

[McGrath] Why would anyone,

maybe other than James Bond, want to do that?

But there wasn't any parachute or harness near him anyway,

so he couldn't have come here intentionally.

[Morgan] So not having a parachute

doesn't mean that this guy didn't exit the plane.

I mean, he might not have had a choice, you know.

[Cantor] We know that cartels have thrown people from airplanes before.

This is documented.

Does this mummy hold a clue, to how drug cartels operate in the 20th and 21st century?

[narrator] In 2017,

the body of a man was found on top of a hospital,

in the city of Eldorado.

It's believed, that he was one of three men thrown from a plane

by a Sinaloa drug cartel.

Could the mummy found on top of the mountain

have been a victim of a drug war?

[Cantor] Did they do this to send a message to intimidate?

Did they do this to punish somebody

or remove them in a particularly spectacular way?

[Morgan] Any rational person has to conclude that,

this man didn't end up where he was accidentally.

[narrator] Forensic analysis reveals the mummy is a male

between the ages of 20 and 40.

He sustained serious injuries before his death.

The broken tibia and fibula in his leg,

as well as other minor injuries.

Including missing an eye and flesh on his face.

Broken legs are pretty common when you've got a fall from a high height.

But you know I think it's pretty obvious observation

that if you fall out of a plane,

you might have a little more than a broken leg.

[narrator] The report estimates that the man died about 15 years earlier.

And that he likely bled to death as a result of his broken bones.

But who he is and how he got there continues to elude investigators.

The reason timeframe means you can look at the flight records.

And these flight records may provide clues as to who this man was,

where he came from and how he ended up where he ended up.

[narrator] A review of airplane crash reports

around that time frame offers up a clue.

The flight records show that a small military aircraft

crashed into Pico De Orizaba, in 1998.

1998, that's one year before the estimated time of death of this mystery person.

Could he have actually been on that plane?

[narrator] The Mexican military shrouded the 1998 crash in secrecy.

The area was sealed off and a rescue and recovery mission was sent in.

But the military refused to reveal any details at all

including who was on board the plane.

[Morgan] If a military plane goes down, that's a pretty big deal

like the government gets involved for that kind of thing.

So it's really strange that there are so few reports

for what actually happened up there.

[Cantor] All we can go on are the press reports

and they report that there were two crew members

and between two and six passengers.

Some press reports say that this plane

was carrying members of Mexico's Secret Service.

Some say it was military staff.

If it was Mexico's Secret Service,

that could explain why he was dressed the way he was.

We just don't know.

[narrator] The plane crashed near the summit at 18,200 feet.

The mummy was discovered more than 1000 feet below that height

with no signs of wreckage around it.

Maybe the reason the military didn't recover the body back then

is because he survived the crash and tried to walk away.

[narrator] Investigators wonder if a man wearing a business suit

survived a plane crash on Mexico's highest mountain,

but then died climbing down.

If you've been in a plane crash staying with the wreckage

increases your chances that rescuers will find you.

But if you've been disoriented from the crash,

suffered a concussion, panicking,

succumbing to hypothermia,

you're not thinking straight.

Any of these factors could have led this guy to make the decision

like I've got to try to get down this mountain,

what other choice do I have?

[Cantor] Remember, it's bitterly cold on this mountain.

These are freezing conditions. It's inhospitable.

Could a survivor of the crash really make it,

1000 ft down the mountain wearing only business clothes?

[narrator] Hypothermia could set in very fast

and the fractures in the man's leg are so severe

that making 1000 foot trek down a mountain would be next to impossible.

[Morgan] If he walked away from the plane,

he must have broken his leg after the crash.

[Cantor] It's quite a theory. It's an extraordinary theory.

But even if true, it doesn't answer the fundamental question,

who was this mystery man?

[McGrath] You'd expect that if this man was a passenger on the flight

that someone would have come and looked for him,

but no one ever has.

[narrator] In a macabre turn,

the mummy now rests in a display case at a museum

in the nearby city of Ciudad Serdan,

relegated to a sideshow curiosity.

But the identity of the man in the suit,

and how he ended up near the top of Pico De Orizaba,

remains hidden to this day.

I mean, maybe this guy is on a secret government flight

and that's why his family was afraid to claim the body.

I mean, we just, we don't know.

Somebody knows how this man got here.

He didn't get there by himself.

You don't get up to the top of mountain in a suit on your own.

So somebody knows how he got there

and either chose not to say or was instructed not to say.

[narrator] In the frozen west of Iceland

lies the Langjokull glacier.

In some places,

the ice is up to 1900 feet deep.

[Dr. Alison Leonard] The Langjokull glacier is huge.

It's 30 miles long and up to 12 miles wide,

so it's almost the size of Dallas.

[narrator] Below the ice,

are the craters of at least two ancient volcanoes.

But even farther beneath Langjokull

is something even more astonishing.

An ancient lava field entwined with a complex series of tunnels.

[Mike MacFerrin] Molten lava flows through these vents

under a hardened surface and if it flows out

it can leave behind a long lava tube.

[narrator] It's here in these caves

beneath the melting glacier

that a dark and violent mystery begins to reveal itself.

In the year 2000,

two archaeologists excavated a site near the Surtshellir tunnels

northeast of Iceland's capital Reykjavik.

Towards the end of the 9th century

Norwegian Vikings set sail for Iceland.

They found this land,

they decided to settle there and because of that,

we have this immensely rich record of archaeological artifacts

that tell us more about their presence on this island.

[narrator] The archaeologists' work is disrupted

when a group of tourists asked them to take a look at a nearby cave.

You enter the cave from this bowl like depression

and as soon as you enter it, you realize this place is immense.

There is no natural light.

It's incredibly dark.

In other parts of the cave the ceiling's collapsed.

It's cold in there.

Snowdrifts have blown in and lingered for years.

[narrator] But it's not the cold that takes their breath away.

It's what they find inside.

What first looks like a pile of rubble caused by a ceiling collapse

turns out to be the remains of a man-made wall.

Before it collapsed, it was at least six feet tall,

spanning the entire 40 foot width of the cave.

It's made of huge blocks of rock, each weighing an estimated four tons.

[Leonard] Building this structure in a dark cave

would have been an enormous undertaking.

But why here?

Was this wall built to keep enemies out, or to keep something in?

[narrator] Part of the wall is crumbled

and as the scientists scramble to the other side

they noticed the cave naturally branches into two different galleries.

In the left gallery, they immediately find some ancient relics.

Three small pieces of lead,

and a lead cross.

[Leonard] The led pieces were probably used

for Viking weight-based economy that relied on silver.

There's also the presence of an amulet

that seems to be in the shape of a Thor's hammer.

[narrator] But even more extraordinary,

they find a massive pile of animal bones.

[Leonard] But what's really creepy,

is that they've been methodically hacked into tiny little pieces.

Were these animals used for food,

or for something else?

[narrator] To learn more about who might have left these bones here,

archaeologists turned to the Norse sagas.

The Norse sagas are epic poems,

epic stories that were written down in the Middle Ages.

And they chronicle the events of the gloried past of the Viking ancestors,

telling stories of feuds

of battles,

and disputes between neighbors,

all of which took place in Iceland.

[narrator] The stories are violent and gory.

One saga recorded in the Book of Settlements

tells the tale of a vicious band of 18 outlaws,

who stole livestock from local farmers in the area.

Could these caves have been used as a base of operation for the raids?

[Leonard] It's an intriguing theory.

Eighteen marauders would certainly go through a lot of food.

Maybe the bones are just the leftovers

after years of hiding out here.

[narrator] But archaeologists have their doubts.

[McGrath] First of all, the enclosure in the rear gallery

is only 23 feet long and 11 feet wide.

It really couldn't have supported a gang of 18 outlaws,

at least not comfortably.

[narrator] Archaeologists pour over the bones looking for clues.

On closer examination,

they noticed strange inconsistencies in the fragments.

[McGrath] Some of the bones appear burnt while some don't.

And they appear to have been meticulously separated.

From the looks of it,

these bones aren't simply meal leftovers.

They seem to have received special attention.

[narrator] There's also no evidence of a water source.

[Leonard] Sure, maybe it was used by a gang

or by several gangs from time to time,

but there's just not enough evidence to support

the idea of any long term or permanent base camp.

[narrator] If the cave wasn't used as a refuge for outlaws,

what was it used for?

The answer may be revealed by unearthing

the ancient rituals of the Viking dark arts.

Archaeologists discover a mysterious 40 foot stone wall,

deep in the lava caves beneath Iceland's Langjokull glacier.

But after analyzing relics found in one of the caves,

they still don't know who built it

and why.

[McGrath] They were so focused on the details

that they lost sight of the big picture.

So they took a step back to re-examine the evidence.

What were they missing?

[narrator] 800 feet from the entranceway in the left gallery,

they discover a stone enclosure constructed in the shape of a boat.

The oval enclosure is 22 feet long and almost 11 ft wide.

The walls are made of boulders stacked three feet high

as a six foot wide entrance at the end.

What is it?

[Cantor] This is called a ship setting.

Going back at least 1000 years,

Vikings built structures in the shape of a ship

and they built this, at sites of religious significance,

worship sites, burial sites.

This shows you how central ships and ship building were

to Viking beliefs, to Viking sense of themselves.

So what is a ship setting doing in a sealed-off cave?

[narrator] Archaeologists start to dig down, hoping to unearth the answer.

And this time around they hit pay dirt.

[narrator] A sandy layer of soil on the floor gives up a collection of glass beads.

It's one of the world's largest collections ever found in Iceland.

[Leonard] These were very special to the Vikings.

They were used for trading,

they were used as currency, and they also used them to flaunt their wealth.

[McGrath] The glass beads are critical find.

But why would the Vikings leave these valuable items on the cave floor.

It doesn't make sense.

[narrator] The spiritual realm of the Vikings may offer some clues.

To the Vikings their mythology wasn't just one set of stories,

it was actually a whole worldview.

So to them, the powerful gods and the giants

were all actually real.

[narrator] Perhaps the most terrifying of them all,

was Surt, the fire giant.

According to Norse mythology,

Surt will rise from the scorching underworld on the day of the apocalypse.

His job will be to lead the destruction of all life as the heavens are torn open.

The Vikings seemed to have viewed Surt as the personification

of Iceland's explosive geology.

Volcanoes, lava flowing and bubbling,

geysers, geothermal activity, when the earth started doing

all of these things around the Vikings in their new environment,

it made sense to attribute them to this fire giant.

[Leonard] It's said in Norse mythology that he had the power

with his immense sword coated in flames to destroy the entire world.

[MacFerrin] It makes sense then.

They would do whatever they could do to cool his wrath.

Maybe that's what was happening here.

Did they do all this to appease the fire giant?

[narrator] The beads and the pile of animal bones

point towards this cave being a site for making offerings to the gods.

But the massive wall near the cave's entrance is still unexplained.

[Leonard] We know that the last bone was deposited around 960

and it seems that the cave stopped being used after that.

So is this the time that that great wall went up?

[narrator] The cross-shaped lead weight may be the key to the answer.

Because this is a Viking site, it seems reasonable

to assume that the amulet was a Thor's hammer.

But in fact, it's much more likely to be a Christian cross.

[narrator] By the mid-1900s, Christianity was seeping into Viking culture,

eroding pagan beliefs.

Perhaps the pagans using this cave decided to become Christians.

[Leonard] Quitting the cave and leaving those pagan artifacts behind

could be a way of saying goodbye to those beliefs.

The deposits could almost be a form of apology.

A way of saying, "We're not going to do these pagan rituals anymore."

It's possible that they built this wall to keep people out

to prevent people from returning to continue to perform pagan rituals.

[narrator] In the end, the archeologists theorize

that the cave was a far more intriguing place than just to hideout for outlaws.

And if the Vikings were trying to appease the terrifying fire giant,

their efforts worked.

As it happens, giving up on the pagan beliefs seems to have had an effect.

The last volcanic eruption to take place in this area was in 930.

This is just a few decades before the caves stopped being used.

[narrator] Desolate Mount Kologet, in Northern British Columbia.

It's just 50 miles

from the Alaskan border in the Kispiox mountain range.

This place is remote. I'd be hard-pressed to find it on the map.

There are howling storms, bitter cold.

This is the kind of place that only the most intrepid adventurers

even think about setting out for.

[narrator] An elite band of hikers ascend the forbidding mountain

6000ft above sea level.

Near the summit, they stumble on a curious sight.

Half buried in the deep snow,

they find the wreckage of a large aircraft.

[Brooke Guzar] It's hard to tell even what type of plane this is.

Is it a passenger plane?

Is it a cargo plane? Or maybe it's something else entirely.

[narrator] On closer inspection,

the wreckage reveals its identity.

It's the remains of a US B-36 peacemaker bomber,

but there's something even more strange in the snow.

A Geiger counter.

[Morgan] A Geiger counter is a piece of technology

that's designed to detect and measure radiation.

The only reason you need a Geiger counter up here

in the middle of nowhere is if you're worried about the threat of a nuclear bomb.

[narrator] If so,

where's the bomb?

On the remote mountains of British Columbia,

the wreckage of an American bomber

and a device used to measure nuclear radiation are found buried in the snow.

What exactly happened here?

On February 13th, 1950

a US Air Force B-36 peacemaker bomber

takes off in frigid temperatures

from Eielson Air Force Base in Fairbanks, Alaska.

Its mission is top secret.

It's the height of the Cold War.

In an effort to hold back the Soviet Union,

the Americans were assembling a fleet of sophisticated aircraft.

[Cantor] The B-36 peacemaker

was the largest strategic aircraft ever built by the United States military.

It had a wingspan of 230 ft, an incredible range of 10,000 miles.

And that means that it was the first bomber

capable of transporting and delivering a nuclear weapon

anywhere in the world.

[narrator] When Flight 2075 takes off that night,

it's part of a strategic exercise to test US nuclear strike capability.

The B-36 bombers flight brute is set to carry it south from Alaska

flying just west of British Columbia's coastline

down to the US Mainland.

From Montana, it would head west for a simulated bomb dropped

over San Francisco.

[Guzar] One thing that wasn't simulated

was that the plane was loaded with a Mark 4, five ton nuclear bomb.

Having this nuclear bomb on board was the only way to test

how the plane and the crew would function in a real situation.

A fully functional Mark 4 contains a uranium and plutonium core

and several thousand pounds of conventional explosives.

This is nuclear material. There is no room for mistakes.

[narrator] But radio dispatches

revealed that just six hours into the flight

distress messages from the crew

start pouring into Eielson Air base.

Crew members report losing altitude at a rate of 500 ft per minute,

just off the coast of British Columbia.

[Cantor] It was around minus 40 degrees that night.

And when it's that cold and ice starts forming on the wings,

the plane may be unable to maintain altitude

and when that happens, you're in serious trouble.

[narrator] One by one, three of the planes' six engines catch fire.

Then radio communications with the base cut out completely.

[Guzar] Once the captain realizes he's lost control over the bomber,

he sets the autopilot towards the pacific ocean and orders the crew to bailout.

[narrator] 12 of the 17 crew members survived,

rescued by the Canadian Navy.

The other five were presumed lost at sea.

Strange thing is they never found the wreckage of Flight 2075.

And if there was a bomb on board, nobody ever found that either.

So, where is it?

[narrator] How does a nuclear bomb simply vanish from the face of the earth?

[Morgan] In the military's investigation,

the crew claimed that they dropped the bomb and that it exploded

3000 ft above the water before they bailed out of the plane.

There's something about this story, it just doesn't add up.

If a nuclear bomb had exploded

it would be a massive catastrophic event,

there would have been a mushroom cloud.

Nobody claimed to see anything like that.

[narrator] It's all very strange.

After the hikers discovered the wreckage,

no one could reach the remote site for over a year.

Then, in 1954 a small US Military demolition team

finally found a way.

They spent nine days gathering equipment and destroying classified parts

of the bomber, so they wouldn't fall into the hands of the enemy.

I asked myself were they also trying to hide the fact

that a plane armed with a nuclear bomb

crashed into the side of a mountain

because that would be incredibly dangerous and destabilizing.

Is that why a Geiger counter was found at the site?

[narrator] Was the military worried that the missing Mark 4

and its core might still be on the mountain.

And the question is, is there still any nuclear material at this site?

[narrator] It would be decades before the final clue would reveal itself

in the melting snow.

Decades after the mysterious crash of Flight 2075,

hikers find an object in the wreckage of a B-36 peacemaker bomber

that may solve the mystery of a nuclear bomb gone missing for decades.

This is the first time the American military had lost a nuclear bomb.

Naturally, people were asking questions.

But we still don't know with any certainty whether the Mark 4 was armed.

On a nuclear mission,

the actual bomb was always kept separate from the fissile core.

And that core was kept in what's called a bird cage.

When it came time to arm the bomb,

the core would be removed from the bird cage and inserted into the bomb.

[narrator] The bird cage is specially designed container

for carrying the 13-pound plutonium core

before it's loaded into the bomb.

Without the core, the Mark 4 will still explode, but it won't be nuclear.

If the bird cage is empty,

it could mean the bomb wasn't armed.

The bird cage is now in the hands of the military

and they refused to disclose any details about it.

If we had just gotten a look inside that bird cage,

we would know if there was nuclear material inside.

And so you and I,

we're just gonna have to wonder.

[narrator] In 2015,

a new potential lead is found in the depths of Haida Gwaii.

A fishermen diving to inspect his next fishing spot,

discovers a large metal object on the ocean floor.

It's vaguely shaped like a bomb.

The Royal Canadian Navy quickly dispatched one of its ships to this site.

Could this be the missing Mark 4?

[narrator] A specialized bomb crew

sends a remote operated vehicle down to investigate.

[Morgan] The footage of this bomb is pretty disappointing.

It's just a piece of junk.

Whatever happened is still a mystery.

[narrator] This is the first time in history

the American military had ever lost a nuclear bomb,

but it wouldn't be the last.

To date, 32 nuclear weapons have gone missing,

where they are nobody knows,

or at least they're not talking.

[Cantor] One takeaway from this incident

and it's not a very comforting one,

is that there may be more near misses than we know about.

There may be more times that a nuclear bomb was armed by mistake

or came very close to being launched or went missing.

The ones we know about are scary enough.

Could discoveries like this one reveal

it's more frequent than we thought?

[narrator] Antarctica is the most isolated place on the planet,

where temperatures can reach as low as -75 degrees Fahrenheit.

It's the only continent never colonized by people.

But there is one creature who not only survives,

but thrives here.

[MacFerrin] Antarctica is teeming with life.

It's home to huge colonies of Emperor, Adelie in Chinstrap penguins.

[narrator] In 2016,

a group of Chinese scientists stumble upon a macabre scene.

An enormous penguin graveyard.

Hundreds of little penguin bodies heaped on top of each other.

This is really upsetting.

What happened here?

[McGrath] It's a killing field of penguins, that's strange.

But what's even more strange is that they're all mummified.

What could have caused this?

[narrator] The scientists estimate that there are hundreds

of penguin mummies packed into the small space.

In some areas up to 15 penguins per square yard.

To have hundreds of these little animals all stacked

on top of each other in one place mummified,

it's what's called a mass casualty event.

[narrator] What could have caused the death of hundreds of penguins?

And why did they all turn into mummies?

Scientists in Antarctica want to know what caused a killing field,

full of hundreds of mummified penguins.

[McGrath] This is a natural environment.

Is it possible a predator got into the colony and wiped it out?

[narrator] Penguins biggest predators are killer whales

and leopard seals.

Leopard seals and killer whales,

they have their prey in the water.

They're not just gonna pile up a bunch of food

and leave it laying around on the land.

On land, birds like skuas prey mostly on eggs and chicks.

But they wouldn't leave their food behind.

So what happened to these penguins?

[narrator] When the scientists examine the bodies more closely

they discover that most of the mummies are chicks.

[MacFerrin] Penguin chicks are vulnerable.

They rely entirely on their parents for food to survive.

They're prone to starvation if their parents can't provide.

[narrator] Could the penguins have starved to death?

[McGrath] Penguins are famously good parents and they share the workload.

They will literally walk to the ends of the earth

to bring back food for their young.

[narrator] Could it be that something prevented the parents

from making it back to feed their young?

In 2013,

150,000 Adelie penguin were found dead from starvation

when an iceberg cut the colony off from the ocean.

But the Chinese scientists studying the penguin mummies

can find no signs of malnutrition.

These penguins were well fed. They didn't starve.

So what could have happened to them?

[narrator] Scientists are baffled.

Perhaps it was some sort of epidemic where they killed off by disease.

[Morgan] A disease would account for the intact bodies

and younger animals tend to be more susceptible to that kind of thing.

[narrator] Researchers have found that penguins

are highly susceptible to infectious diseases, including salmonella,

E.coli and Avian pox viruses.

As tourism rises in Antarctica,

transmission of these diseases has risen in turn.

And the scientists examine the bodies,

the mummified remains show no visible sign of disease.

They didn't get sick and die. They weren't abandoned. They didn't starve to death.

Nothing ate them. So what could have accounted for all these deaths?

[narrator] Radiocarbon dating provides an intriguing clue.

It reveals one group of the penguins died 200 years ago,

while the others died 550 years before that.

We're talking about two separate events here.

What could have happened that would have killed so many birds 500 years apart?

[narrator] Researchers look for clues around the carcasses.

They study the sediment around them,

The sediment showed signs of increased precipitation and heavy flooding.

Baby penguins begin with fluffy feathers to keep them warm.

They don't develop waterproof feathers until they're about nine weeks old.

Normally this is fine.

These chicks are born in the winter and it's an extremely dry cold.

[Morgan] But if baby penguins' down feathers do get wet,

that liquid gets trapped against their body

and they become susceptible to hypothermia.

Baby penguins are not designed to handle damp weather,

which means that a single rain event

is enough to wipe out a lot of nestlings.

[narrator] The researchers take ice core samples

to look for clues of any abnormal weather events

dating back to the times of the die-offs.

They were able to confirm that these deaths coincided with an extremely wet event.

It's an indication that this part of Antarctica

was hit with a heavier wetter type of snow than usual.

[narrator] Analysis of the sediment around the mummified penguin chicks

shows flooding due to increased snowmelt.

These penguin chicks from both time periods

died either of hypothermia or drowned when their nests flooded.

[Morgan] Once they died, their bodies froze

and when the water receded,

the Antarctic winds were enough to mummify their bodies.

[McGrath] It appears that two climatic anomalies occurred.

There was too much moisture in what is usually a dry and cold place.

When the weather returned to normal,

this place turned into an eerie penguin graveyard.

[MacFerrin] Throughout time, there's a delicate balance

between animals and their environments.

Even the tiniest shifts in climate can prove lethal.