Original subtitles

NARRATOR: Worldwide, 36 billion cameras

are watching us -- on our streets, at work,

and in our homes,

they capture things that seem impossible.

Science says this shouldn't happen.

Do you see that?

NARRATOR: Experts carry out forensic analysis

of these unusual events.

Wow, what a blast!

[screaming]

This doesn't make sense.

There has to be some sort of explanation.

What else is going on here?

NARRATOR: Coming up, on Zombie Island,

is this funeral the end or just a new beginning?

Did I just -- is that a hand?

Local legend suggests that these bodies can

make their own way back to the village.

NARRATOR: Three friends encounter a series of

mysterious explosions.

That energy went off sequentially --

[makes rapid noise] just like that,

like a huge run of explosives.

To me, it suggests that something is supercharging

this explosion.

NARRATOR: And the rise of Sky Walker

at an African ceremony.

This is really wild.

This man appears to be defying the laws of physics.

There certainly seems to be some sort of force

lifting this man into the air,

but the question is, what is it?

-NARRATOR: Bizarre phenomena. -Oh, my God. [gasps]

NARRATOR: Mysteries caught on camera.

[screaming]

What's the truth behind this strange evidence?

Now, Manado, Indonesia.

May 5th, 2020.

In a graveyard, a mourner at a funeral films

as a man is laid to rest in a coffin with a glass window.

LOVELL: Oh, my gosh. What was that?

What was that?

Did I just -- is that a hand?

NARRATOR: The dead man's hand seems to be moving inside

the coffin, waving like a desperate cry for help.

It makes you wonder if rather than a funeral,

we're actually watching a huge and horrifying mistake.

NARRATOR: The grieving family doesn't seem to notice

that their dead relative appears to be

moving inside their coffin,

or perhaps they expect it.

On this particular island,

some locals believe their relatives bodies can be very

active indeed, after their death.

Years after a person's funeral, relatives

dig up their decaying bodies and throw a party for the dead.

Some people refer to their dead as

the "Rolang," or the corpses that stand up.

I think we would more likely refer to them

as "the walking dead."

NARRATOR: Shocking images show the living as they bring

the dead back to their villages for rituals

and ceremonies.

They'll take their dead aunt or their dead grandmother

for a walk from the burial cave

back to the village, dress them up a bit,

give them something to eat, take them back.

So they never seem to part company with their own dead.

NARRATOR: Indeed, some corpses are said to not even need

their relatives' help.

Local legends suggest that these bodies can make their own

way back to the village with the assistance of shaman.

NARRATOR: Shaman, powerful local priests,

are said to be able to use zombifying

black magic to reanimate the corpses

so they can stagger by themselves back to

their former homes.

From an Indonesian point of view, where they have

the belief that the dead can potentially,

with the help of a shaman, rise and walk,

then perhaps it wouldn't be as alarming to them that

somebody was moving within their coffin,

even though they were absolutely, empirically dead.

NARRATOR: Physician Siobhan Deshauer looks at the video

and wonders if this may not be a corpse

but a living person trapped in a nightmare.

While it's very rare,

there's some medical conditions where a person will

appear to be dead, but they're really not.

The Victorians were horrified and almost obsessed with

the thought of being buried alive, so much so that they even

had arrangements to have a small bell in the coffin,

just in case they needed to warn the outside world that

they weren't actually dead.

We may mock the Victorians, but here we are

with the possibility that it's actually happening today.

NARRATOR: The horrific possibility of being

accidentally buried alive

may seem like something that modern medical science

conquered decades ago, -[man shouting]

but terrifying recent accounts come from all over the world.

Even doctors will diagnose them as having deceased.

And sometimes, these people can wake up just before

an autopsy or just before or during a burial.

NARRATOR: In 2018, an inmate at a prison

in Spain is certified as dead

by three doctors after being found motionless in

his cell. -SAMUEL: Subsequently,

he was sent to autopsy, and he awoke before they cut him open.

NARRATOR: But the horror can be much worse.

In the same year, a 37-year-old woman

from Brazil is buried

after being pronounced dead by septic shock.

11 days later, locals living near the cemetery hear

screaming from her grave.

[distant screaming]

Soon after, desperate family members are

said to have exhumed her corpse.

What they find is as tragic as it is shocking.

The lid of her coffin is loose, and the woman

is covered in injuries that weren't there

when she was buried.

It's as if she had been trying to escape,

but ended up dying a terrifying death,

trapped in her own coffin. -[distant shouting]

Being buried alive, that is my worst nightmare.

NARRATOR: Biologist Leslie Samuel discovers a medical

condition that can make it seem like a patient has died,

one that baffles even modern medicine.

Catalepsy turns the living into the dead

by dropping the heart rate and breathing down to levels

below the norm for humans.

NARRATOR: A person suffering from catalepsy can also

become stiff as though going through rigor mortis

and will be less sensitive to pain.

Doctors around the world have been fooled by conditions like

catalepsy, so we can't rule it out at this point.

SAMUEL: The way that hand kind of raises up as

if this person is coming out of a deep sleep,

it kind of leads me to believe

that this person was alive the whole time.

Could it be that

Indonesian doctors have just made a mistake,

and they're about to bury this guy alive?

NARRATOR: Coming up, does the corpse have a companion

inside its coffin?

If nothing else,

this is a great advert for being cremated.

NARRATOR: And Matt Kutcher investigates

as a city mysteriously erupts from below.

That energy went off sequentially [makes rapid noise]

just like that, like a huge run of explosives.

NARRATOR: On an island famous for its zombies,

a mourner films as bizarre movements appear

to take place inside a coffin.

Biologist Greg Szulgit suspects

the shocking clip is horrific evidence that

the corpse is not alone in its casket.

Another possibility is that a rat or some

other animal has got inside of the coffin,

and it's feasting on the corpse,

which, of course, means that it could be moving the arm around

as it chews on the body.

Could a rat-infestation have caused his hand to move?

[rat squeaking]

NARRATOR: Rats in morgues are a problem all over the world.

In 2017 in India,

the body of a 21-year-old woman

was found chewed by rats as it lay in a hospital.

In 2007 in Washington, D.C., rodents get into

a hospital and find their way to the building's morgue.

Rats were chewing on bodies.

And if rats can do that in well-maintained hospitals

in America, certainly in a rural part of Indonesia,

we would expect that rats should be able to access a body.

And that's pretty repulsive to think of a coffin

overrun by rodents.

NARRATOR: Whatever was moving inside the coffin,

the truth is now buried under six feet of earth, and so far,

no one has been brave enough to dig up the body to find out.

The sad thing about this case is

that will actually never know the truth.

So if he did come back to life,

I hope that his second ending was a swift one.

If nothing else,

this is a great advert for being cremated.

NARRATOR: Now,

Kaohsiung City, Taiwan.

July 31st, 2014,

12:16 a.m.

Three friends driving home from a night out

wait at a junction in the center of town.

Looks like a very quiet night that you would see

in any city. -NARRATOR: Then...

NARRATOR: A mysterious explosion rips through the road.

[inhales sharply] Oh, my God.

NARRATOR: A moped rider narrowly

misses the blast, then swerves to avoid

a huge fireball rising into the air.

Wow, this is really bad.

NARRATOR: The panicked men tried to escape,

but a thick cloud of smoke blocks their path...

[speaking in foreign language]

...followed by a raging column of fire.

It looks like someone just opened the gates of Hell.

NARRATOR: Something cuts the power along the street.

[speaking in foreign language]

NARRATOR: And the car is rocked by another blast of flames.

WOLSHON: It almost looks like a war zone.

I've never seen anything like this before, ever.

NARRATOR: Military historian Martin Morgan believes

these explosions could be

a terrible legacy from World War II,

when Japan brutally took over the islands in the Pacific.

As the Japanese strengthened their island outposts,

they tended to fortify them, and these islands are often

lava rock,

and lava rock can be quite easy for tunneling.

So the Japanese made use of

the terrain that was available to them,

and these islands are extensively tunneled.

NARRATOR: Japanese troops hid in these tunnels to mount

surprise attacks on invading American forces.

U.S. casualties were twice as high on some islands,

where troops had to wage so-called cave warfare,

than on islands with standard beach defenses.

On Iwo Jima alone,

almost 7,000 U.S. troops were killed.

There are tunnels today at almost every other

Japanese island outpost --Taiwan's no exception.

The bedrock below the surface is

honeycombed with an extensive Japanese cave network.

NARRATOR: In Keelung, Northern Taiwan,

a 164-foot-long tunnel served as a bomb shelter and for

ammunition storage throughout World War II.

And in Kaohsiung, an 850-foot-long tunnel

was carved deep underground and used by Japanese forces

as a command center.

Historians believe

there could be scores of munitions tunnels throughout

Taiwan, abandoned

by the Japanese at the end of World War II.

Who knows how many weapons were left behind by

the Japanese in Taiwan?

Maybe some of them were hidden inside these tunnels.

NARRATOR: But Morgan suspects

the blast could be the result of a deliberate

and devastating tactic used by the Japanese

in their fortified tunnels.

MORGAN: American fighting forces learned a dark lesson,

and that is

that when you approached a Japanese tunnel,

you had to be very careful with it, because they were

often booby trapped.

They might set off a landmine or a hand grenade.

NARRATOR: Morgan believes one of these tunnels could have been

disturbed by modern construction workers,

causing the terrifying blasts seen in the footage.

There's a possibility that there may be unexploded booby traps

on that island to this day,

and we might be seeing one finally going off,

decades later.

NARRATOR: But engineer Brian Wolshon

finds that the city has gone through

huge regeneration since World War II,

both above and below ground.

So any unexploded ordnance or booby traps,

they would have been discovered long ago in prior

building construction.

Clearly, this must have been caused by something else.

[speaking indistinctly]

♪♪

NARRATOR: Matt Kutcher has over 20 years experience

as a top Hollywood pyrotechnics expert.

Go!

He discovers new camera footage of

the explosions that rock Kaohsiung

that could provide a clue.

-What do you got here? -Watch this, watch this,

watch this. -[explosion blasts]

-Wow. -KUTCHER: I know, right?

That energy went off sequentially [makes rapid noise]

just like that, like a huge run of explosives.

Chased it all the way down the road.

It did, all the way down the road.

It's one linear line.

NARRATOR: In a fraction of a second,

the linear blast turns everything to dust.

Kutcher wants to figure out

what sort of flaming explosion can progress in

a straight line.

We're gonna need some fuel and some dirt,

mix it up with some explosives

and see if we can't create a linear line

that resembles that video.

-Yeah, we could do that. -Let's go to work.

NARRATOR: Kutcher suspects the flames come from

some kind of fuel that must have been

contained in a long line to create such a powerful blast.

Gentlemen, gentlemen.

So here's -- here's my trip.

We're gonna take explosive material and wrap it as

if it was a pipe -- with the fuel inside of it,

we'll atomize it at a very great rate of speed,

and if we add an ignition source,

it'll go apocalyptic.

NARRATOR: Coming up, can Matt Kutcher figure out

why this city exploded?

Okay, in three, two, one, go!

NARRATOR: And, in the land that produced

the biggest dinosaurs...

What is that...?

...the most massive lake monster ever caught on camera.

This thing looks like the Loch Ness Monster on steroids.

NARRATOR: In Kaohsiung, Taiwan, an extraordinary blast shoots

through the city.

Matt Kutcher suspects

it's caused by some kind of fuel contained in a long pipe.

He and his team prepare a line of canisters

filled with fuel and rigged to blow in sequence.

It'll be 1 through 9 -- we'll number them,

and once I fill them with fuel

and step away, we'll go to the board -- 1 through 9.

We'll try to create that same linear

charge that we see in the video.

NARRATOR: This is an extremely dangerous experiment

that should be only conducted by experts like Kutcher

and his team, so don't try it at home.

[indistinct exclamation]

Okay, in three, two, one, go!

[explosion blasts]

[explosion blasts]

That explosion traveled right down the line.

That was beautiful.

[explosion blasts]

I mean, you can see if we scaled this up, well,

it would create a channel bigger than what we created.

But I think it matches the explosive pattern

we saw in the video quite well.

[explosion blasts]

Right? Like [makes rapid noise] ka-boom!

NARRATOR: The result gives Kutcher

an idea about where the explosion originated.

This was actually probably a sewer line that was, uh...

restricting the explosive charge, which then

made it worse -- they have this massive amount

of flammable, combustible material in them.

Maybe that's what it is that exploded.

NARRATOR: But what kind of gas could have caused

such a powerful series of explosions inside a sewer?

After the blasts in Kaohsiung, eyewitnesses report

seeing flames reaching as high as a hundred and fifty feet.

Over two and a half miles of street are blown open,

leaving a six-foot-deep trench in the road.

VITTERT: The effects of this explosion are devastating.

It overturns trucks and causes

a complete blackout of the electrical grid.

NARRATOR: 32 people are killed and more than 300 are injured

as a result of the blasts.

In some cases,

there were victims that were actually thrown four

stories up and found on the roofs of buildings.

NARRATOR: And this was no regular gas leak.

A standard gas leak would not

cause nearly this level of destruction.

To me, it suggests that

something is supercharging this explosion.

Brian Wolshon finds that

at 8:45 that evening, a local petrol

chemical firm logs a pressure drop in one

of their pipelines running through the sewer system.

Over 10 tons of gas leaks into the sewer

for more than three hours before the first explosion.

That's a heck of a lot of gas.

[hissing noises]

NARRATOR: The pipe is leaking

a highly volatile gas called propene.

It's a substance widely used in the plastics industry.

It burns hotter than propane and is heavier than air.

What we have here is almost

a three-mile-long pipe bomb ready to explode.

NARRATOR: It takes five months and over 60 million dollars

to repair the damage, but the threat of

an apocalyptic blast still lingers to this day.

WALDER: Everything's fine one second,

and then completely destroyed the next.

It must have been absolutely terrifying for anyone there.

NARRATOR: Now Nahuel Huapi Lake, Bariloche, Argentina.

♪♪

January 21st, 2020.

A man filming the water

notices a strange movement in the distance.

Is that -- what is that...?

HYDE: This is strange.

There is something that's happening in the middle.

Something is coming up and going down again.

Wow, that's big.

NARRATOR: This is no wave.

In fact, it's moving in the opposite direction

to the waves.

BLACKBURN: This is some really extraordinary video,

because it appears to show

an incredibly long creature swimming through

the calm waters.

This thing looks like the Loch Ness Monster

on steroids.

NARRATOR: Nahuel Huapi is a massive 200-square-mile lake

that plunges to nearly 1,500 feet, deeper

than the Empire State Building is tall.

It's big enough to house a monster.

Stories of this strange

water beast have been told for hundreds of years.

Sightings have been documented in Argentina and Chile,

and they describe this leathery water serpent.

NARRATOR: Locals call it Nahuelito.

In 1922, an American gold prospector and former sheriff

named Martin Sheffield reports

seeing a huge water creature in the same area where

the footage was shot.

Sheffield described a long creature

with fins and a swan-like neck.

NARRATOR: Surveys find half of the people living in this region

believe the water beast is real.

Descriptions of its size

seem incredible, even for a lake monster,

but this film suggests

Nahuelito is a seriously big beast.

Many of the locals

think this footage is more proof

that the creature really does exist.

NARRATOR: Image analyst Ben Radford tries to size up the object

moving through the lake.

There seems to be something out in the water at

this line, and it continues to move across the line

to different places.

It appears to be either one creature

that's moving across or one fantastically large creature

that's literally a quarter-mile long.

It's not clear what it is,

but there does seem to be something dark in the distance

that's moving from right to left.

NARRATOR: Coming up, is this a super-sized

survivor from a time of giants?

Once swish of their tail could cut you right in half.

NARRATOR: And in Africa,

a mysterious man seems to float in midair.

People claim they're able to draw on some miraculous energy

from the spiritual realm in order to do this.

NARRATOR: In Argentina, a man films

what looks like the biggest lake monster ever captured

on camera lurking in the waters of Lake Nahuel Huapi.

Dustin Growick finds this part of the world was once

a land of giants.

This area of Argentina known as Patagonia was home to some of

the largest creatures who have ever walked the face of

the Earth.

NARRATOR: If it is an enormous creature,

it would fit a pattern of super-sized dinosaurs that

evolved in this part of the world in the ancient past.

It's obvious from the footage

this is a very long creature, which

immediately makes me think of something prehistoric.

NARRATOR: In 2013, a farmer in Patagonia comes

across a gigantic bone buried in the dirt.

Paleontologists find that it's an eight-foot-long

dinosaur thigh bone, the largest ever to be

discovered -- experts believe

it belonged to the mighty Titanosaurus.

At over a hundred and twenty feet in length,

it's longer than ten elephants standing end to end

and may have been the largest creature

to ever walk on land over 65 million years ago.

GROWICK: One swish of their tail could cut you right in half.

They were eating thousands of pounds of food a day.

In fact, when they went to the bathroom,

we're talking about three gallons

every time they went number two.

NARRATOR: Dinosaurs are known for being big,

but here in current-day South America,

they were incredibly big, and scientists can't explain why.

Paleontologists have discovered giant creatures

of this region were not just limited to the land.

Enormous marine reptiles once hunted

Patagonia's ancient waterways.

Things like Mosasaur, Ichthyosaur,

and Plesiosaur, a long-neck, carnivorous

aquatic animal.

NARRATOR: In 2019 paleontologists Excavating near

a Patagonian lake

discover the fossil of a giant

xiphactinus fish measuring 20 feet long,

the size of a small school bus.

GROWICK: These guys were incredibly scary,

swimming at upwards of 40 miles an hour, giant teeth, and would

eat pretty much anything

they came across -- one xiphactinus specimen was found

with an entire undigested six-foot-long fish in

its stomach.

That's a size of me, a fully

grown human being, swallowed in one bite.

BLACKBURN: Today, the great white shark is

the apex predator of the ocean.

But this thing could have literally eaten it

for breakfast.

It's possible these fish cruise along the top of

the water, something I definitely would not

want to be kayaking anywhere near.

NARRATOR: It's possible certain types of this creature

grew even bigger as they have evolved over

the millennia.

MORGAN: Because of the remoteness of the area,

this particular lake is a good candidate for being

the natural habitat of an ancient dinosaur-like

swimming creature that's still alive.

Maybe not the original creature, but the descendants of

this creature,

and it may be that we're looking at footage of it.

NARRATOR: Whatever is lurking in the lake,

the authorities are taking no chances.

The authorities have banned people going onto it

after dark.

So what do they know that we don't?

BELLINGER: This lake is absolutely massive.

There are plenty of corners for this creature to hide,

as long as it might desire.

So until this creature chooses to surface again,

it's gonna remain a mystery.

♪♪

NARRATOR: Now, Northwestern Zambia, Africa.

August 2018.

In a rural Village, a camera

films an object hanging in midair.

-Oh, my God. Wow. -This is really bizarre.

NARRATOR: It's a man,

and he seems to be levitating 10 feet above the ground.

This is really wild -- this man appears to be

defying the laws of physics.

The strangest part is when these officials with

the sashes come on, and it's almost like

they're telling people, "Put your cameras down.

You can't film this."

There certainly seems to be some sort of force

lifting this man into the air,

but the question is, what is it?

NARRATOR: The average human weighs 136 pounds.

Lifting that kind of weight requires

some kind of known physical force.

But author Jeff Belanger finds

reports that seem to defy explanation.

Legend and lore the world over has talked about some people

having the ability to levitate.

These people claim.

they're able to draw on some miraculous energy

from the spiritual realm in order to do this.

NARRATOR: Many Catholic saints

are believed to have this bizarre ability.

St. Francis of Assisi is said to have hovered

high in the air during prayer in the 13th century.

In the 17th century,

St. Joseph of Cupertino was said to levitate while

saying mass.

During that time, anywhere in the world,

really, talk of levitation would be witchcraft.

St. Joseph was confined to a cell for this

very practice.

NARRATOR: Levitation is also associated with sinister

poltergeist phenomena.

In 1977 in London, England, 11-year-old

Janet Hodgson was said by eyewitnesses to have levitated.

She claimed that she was possessed by

a man who lived in the house years before.

Many people say that they actually saw her levitating.

Even passerbys and say that they can see her through her

bedroom window, levitating above the ground.

NARRATOR: Coming up, is this man

being lifted by a higher power or dark forces?

There's a ritual where a shaman will perform,

and during the ceremony, will actually rise up above

the ground.

NARRATOR: And cabin fever -- as an airplane fills with

a strange smog.

So you're strapped into a plane seat.

There's nowhere to run, and it looks like

the plane is on fire.

NARRATOR: In Zambia, multiple cameras,

capture a mysterious man who appears to be levitating in

front of an astonished crowd.

Jeff Belanger wonders

if the clip shows a man who claims to have

supernatural powers.

Judging from the costumes being worn and the chanting

and the music playing behind this whole event,

it looks like he's some kind of shaman.

In many African cultures,

it's believed that Shaman are able to travel between

our world and the spiritual realm

and even have the ability to heal people.

So this gives them an elevated social status.

NARRATOR: Shamans in some regions of Africa

are still thought to possess supernatural powers.

A West African shaman

is filmed in astonishing footage shot

in 2016,

appearing to kill a man and then miraculously bring him

back to life.

Scientists believe it's nothing but a gruesome magic trick,

but the crowd are transfixed by the shaman's apparent

command of both life and death.

They believe what they witnessed was real.

NARRATOR: Other shamans are said to be able to

enter a deep trance state and somehow defy gravity,

like the man in the footage.

There's a ritual where a shaman will perform at night

in a ring of fire,

and during the ceremony, will actually rise up above

the ground.

NARRATOR: When historian Karen Bellinger

discovers the month in which the footage was shot,

she finds it coincides with an ancient ritual.

This region is known for a very specific,

very special ritual called the Makishi Masquerade,

and it happens every August -- this celebration marks

the end of an initiation period for young boys in

this society known as the mukanda.

The event involves boys ages

8 to 12, where they'll spend three months in

the bush, and it symbolizes the death of their childhood.

For the mukanda, this has an educational function.

You're learning survival skills.

You're learning about sexuality,

about religious beliefs, social structure,

and everything else they need to be adults.

NARRATOR: Throughout history all over the world, young boys

participate in extreme rites of passage to signify

the end of their childhood.

The Mandan tribe of North America

had a really extreme ritual in which young boys would have

a strip kind of cut open in their skin, in their chest

and shoulders, and a thick rod of would thrust through.

They would then be hung by that

until they passed out from the pain.

NARRATOR: The young boys would then have their

little fingers hacked off by a tribesman.

The pain was not pointless -- it was meant to secure

the approval of the spirits

and attune them to the spiritual world.

The Satere-Mawe people of Brazil have a particularly

shocking coming of age ceremony

where the young people put gloves on their hands,

but the gloves are lined with bullet ants.

NARRATOR: Bullet ants, known as the world's most painful

insects, are named for the extreme agony

just one sting can cause.

These are intensely

painful stings that they received dozens of in each hand,

and they have to leave the gloves on for

several minutes.

The pain causes them to go into a trance-like

state before they're able to take the gloves off.

NARRATOR: Athena Brensberger studies the clip

closely and spots a wooden pole,

erected at the height of the apparently floating man.

The way this man is positioned

would indicate there's a thin wire that

he's holding onto and possibly balancing on.

You could see a pole, which would make me think if

there's a wire, it may be tied between the trees and the pole.

David Blaine's got nothing on this guy.

He's doing this in the middle of a crowd.

They've all got camera phones.

It's definitely daring -- if it's a wire,

it's got to be like razor-thin, and I mean, razor.

It's got to be painful.

NEMZER: If you watch the person who's in the video,

this is a particularly good example

of a levitation or a suspension, if you will, because

not only is there absolutely nothing above them,

but it's done outdoors.

So you know it's not relying on any of

the technical aid of what you would get in

a fully-equipped theater.

Normally, when you observe a tightrope walker,

you can see a big, sturdy wire that they're balancing on.

This man must be using an incredibly thin wire

to present the illusion that he's floating in mid-air.

SZULGIT: He's not just walking from one

side to the other, he's dancing --

the strength and balance that this must take are

incredible -- a performance like this must take years to master.

NARRATOR: Reports of the ceremony confirm

this man isn't trying to fool the crowd.

He is trying to entertain them.

The adult man is taking part in the celebrations

after the initiation ritual.

The officials are keeping the crowd under control

so the man doesn't lose

concentration and suffer a terrible injury if he falls.

When young kids in Western society finish school,

they'll go to the prom.

They'll go out for a nice dinner.

But this Makishi performer,

he's pulling out all the stops for these boys who have passed

their initiation ritual with flying colors.

NARRATOR: Now, Jacksonville Airport, Florida.

♪♪

August 11th, 2019.

A plane prepares for takeoff when suddenly...

That is insane.

The cabin fills with a bizarre mist.

Panic rises as visibility drops.

This whole flight looks like it's going up in smoke.

So you're strapped into a plane seat,

there's nowhere to run, and it looks like

the plane is on fire.

[sounds of commotion]

NARRATOR: This seems to be the start of a horrific tragedy.

Over 45,000 people have been killed in plane disasters

since 1970.

Mechanical failures, including engine fires, are

the cause of over twenty percent of all

fatal plane crashes.

But when former CIA agent Tracy Walder checks reports,

she finds no record of an engine fire

on the plane that day.

So I think that there's something else going on here.

NARRATOR: Coming up, has a passenger

brought a carry-on catastrophe aboard this jet?

They are attacking huge amounts of energy into

tiny spaces,

making them highly unstable and leading to a big risk of

fire and explosions.

NARRATOR: In Jacksonville, Florida,

passengers on a plane

waiting to take off are shocked when

a strange, thick fog begins to fill the cabin.

Liberty Vittert wonders

if something in someone's luggage has exploded --

not a bomb,

but an everyday piece of technology --

a phone, a laptop, or a tablet.

Lithium ion batteries are packing huge amounts of energy

into tiny spaces,

potentially making them highly unstable and leading to a big

risk of fire and explosions.

NARRATOR: Billions of modern devices run

on lithium ion batteries.

Some of the chemicals that transmit

an electrical charge within these batteries are flammable.

In 2010, lithium batteries being carried from Dubai to

Cologne on a cargo flight

overheat and ignite, causing a lethal fire to break out,

killing everyone on board.

It's only recently that

are travel organizations have recognized

how dangerous these batteries can be -- in some cases, lithium

ion batteries are no longer allowed in checked luggage,

where a fire could start and go undetected

in the cargo compartment.

But now this danger has just moved to the overhead bins,

where carry-on bags filled with batteries are placed right

next to the passengers,

and you never know when one might spark up

and start a fire.

NARRATOR: But Ashanti Davis spots

the mystery fog is pouring from the overhead vents

and suspects this could be a substance even more

toxic than smoke from an overheated battery.

Could chemicals from the complex mechanics of

the aviation system be leaking

into the air conditioning system?

Exhaust systems should filter out these poisonous gases,

but there's always a risk that some could seep in, and the more

that seeps in, the more the effects.

It may seep in through cracks and doors,

or through the heating baffles inside the plane.

A hundred and thirty seven Japanese passengers faced

this horror during a flight in 2018.

A damaged power unit caused a lubricant to leak into

the air conditioning system, causing some kind of mist to

fill the cabin.

This video looks almost similar to that scenario.

ORZEL: The passengers on the Japanese flight

forced to evacuate onto the runway,

having just inhaled lubrication oil.

Many of them were very sick afterwards.

NARRATOR: But Liberty Vittert thinks

the behavior of the passengers

in the footage rules out a deadly chemical leak.

If this was some type of poisonous chemical,

the crew should be evacuating the plane, since they're still

on the ground, and people should be getting very dizzy.

So there must be something else going on here.

NARRATOR: Physicist Chad Orzel finds the temperatures

outside the plane could have triggered a terrifying

smog inside.

ORZEL: This plane is in Florida, which is a very humid region.

This looks like actual fog.

So could this be related to some strange weather phenomena?

NARRATOR: The temperature recorded at the airport that

day was a scorching 97 degrees.

A plane's air conditioning system works by rerouting

excess hot air from the plane's engine.

This air is cooled by passing through a series

of mechanical chambers and turbines before entering

the cabin.

This complex cooling process

generates condensation as the air reaches the passengers.

So when that are changes from hot and humid to cold,

some of that condensation will actually show up as a mist.

NARRATOR: The mist is confirmed by the airline

to be an unusually high amount of water vapor,

but the fear and panic of the passengers is real

and poses a significant danger.

They're lucky that people didn't

go stampeding towards the exits.

While the mist itself may be harmless, any unexpected event

on a plane risks setting off a panic among the passengers,

which itself can be deadly.

NARRATOR: In 2010, a stampede on a Congolese airplane

in flight unbalances

the plane and causes it to crash with the loss of

20 lives.

The cause of the panic is rumored to

be a smuggled crocodile escaped from a passenger's bag.

Airplanes are such sophisticated machines.

Despite the best engineering and design,

there's things that can go wrong.

Even if this mist is not poisonous,

a flight where you can't see

your fellow passenger is a recipe for disaster.

[people shouting]