Original subtitles

-[camera whirring] -[suspenseful music playing]

[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."

[man] Do you see that?

[narrator] Experts carry out forensic analysis

of these unusual events.

Wow, what a blast.

[explosions]

[woman screams]

This doesn't make sense.

There has to be some sort of explanation.

What else is going on here?

[camera whirring]

[narrator] Coming up.

In Texas, a doll mysteriously comes to life.

Uh, no. [gasps]

[narrator] Are these crystal tears a miracle or a curse?

This is one of the most gruesome

human body phenomena I have ever seen.

[narrator] And a speeding fireball

tears along the freeway.

Has a wannabe superhero gone bats with his car?

Somebody figures,

"Okay, I'm just gonna take my jet powered Batmobile

out onto the road and fire it up."

[engine roaring]

This certainly takes the word "hot rod"

to a new level.

[camera whirring]

[narrator] Bizarre phenomena.

Oh, my God. [gasps]

[narrator] Mysteries caught on camera.

-[woman screams] -[narrator] What's the truth

behind this strange evidence?

-[static] -[theme music playing]

[narrator] Now, Dallas, Texas.

August 2nd, 2020,

house sitter Holly Armstrong is home alone

when she hears a strange sound

coming from the closet.

[heels clicking]

[Holly] Oh, my God.

Oh, my God. Oh, my God.

[Kiki] Uh, no.

[gasps]

Inside the door is a doll

and its feet are clicking together.

[heels clicking]

It looks like this doll has just come to life.

[ominous music playing]

That click, click, click of the heels,

it looks like this doll is possessed.

And then, one leg begins to rise.

I've seen a few creepy dolls in my lifetime,

but this takes the cake.

[narrator] Holly has no rational way to explain

the doll moving on its own

and gets out of there fast.

[Holly] Oh, my God.

Oh, my God. Oh, my God.

You can hear the fear

in that woman's voice.

She is clearly freaked out.

[narrator] Every child has a toy or a doll

that they treasure.

But sometimes, something sinister

seems to move in.

Mallie Fox is familiar with accounts of dolls

supposedly haunted by troubled souls.

Rumors of possessed dolls

are rife in the world of paranormal.

[narrator] One of the most famous haunted dolls

in America is Annabelle.

Supposedly inhabited by the spirit

of a deceased seven-year-old girl.

[Mallie] It looks like a Raggedy Ann doll.

It's from the 1970s.

Apparently, the mother bought it for her daughter.

[ominous music playing]

[Mallie] And when she brought it home,

people were getting scratched.

Then, they called a demonologist,

because some people think it's demonic,

Ed and Lorraine Warren.

And they came in and they said,

"Oh, yes. This doll is haunted.

It's possessed."

Anybody that would come in contact with it

could be harmed.

[narrator] Annabelle spawned several movies

in the multimillion-dollar The Conjuring franchise.

But she's not the only doll

that's supposed to be possessed.

In 2017 in Peru,

a kid's plastic toy doll

is filmed moving and speaking.

[narrator] Normal behavior for mechanized toy.

Except when they open up the battery pack,

-it's empty. -[woman gasps]

[woman speaking]

So, where is her power coming from?

[narrator] In England, another doll, Elizabeth,

is said to behave even more strangely.

Dressed in a bridal outfit,

her owners complained she hates married men

and will attack them.

There are reports that people have been scratched.

She's not your normal average everyday doll.

[narrator] Biologist, Kiki Sanford,

discovers there are psychological reasons

why humans might find dolls creepy.

When we see a machine, a robot,

that looks like a machine,

we think of it as friendly.

But then, when they start looking really close

to what a person looks like,

but not quite right,

we can tell and it makes us feel uncomfortable.

It triggers a reaction

called the uncanny valley effect.

[narrator] But psychological factors can't explain

why this doll, which is not mechanized,

is moving.

We're always on edge waiting for dolls like this

to stand up and take a life of their own.

What is horrifying about this clip

is that the doll is doing exactly that.

[ominous music playing]

[narrator] Nick Householder thinks the answer may lie

in the earth beneath this apparently haunted house.

It could be possible that there's something

in the environment that's causing the doll to move.

Could this, for example, have been an earthquake?

Texas is seismically active

and has experienced a number of earthquakes.

There was an earthquake reported in Dallas

in early August.

[narrator] On August 9, the US Geological Survey

reports a minor quake

registering 2.3 on the Richter scale.

Just enough to make your house shake.

But the phenomenon was witnessed in this closet

on the 2nd of August.

There must be something else

specifically making the doll's legs move.

[narrator] Entomologist, Kevin Kasky,

has been called to many allegedly haunted houses.

Scratches on the walls,

pets staring at one particular spot.

Hmm.

I wonder what that could be.

Well, before you go calling a priest,

maybe you should call an exterminator.

No matter how clean you are,

from the moment you move in,

there are things living

within the walls or the ceilings of your house.

It could be rats.

It could be mice.

There could even be bats scurrying around in there.

These housemates from mites to large rats,

all have the ability to move our stuff around.

Sometimes making it seem as if it's moving on its own.

[narrator] In 2017,

a British woman got a nasty surprise

when she opened her niece's doll.

She found it completely infested with maggots.

Could an infestation of critters

be making those doll's legs move?

-[narrator] Coming up. -[Holly] Oh, my God.

Oh, my God. Oh, my God.

[narrator] Does this house have uninvited guests?

Clicking doll heels

should be the least of Holly's worries.

[ominous music playing]

[narrator] And these diamonds

are not a girl's best friend.

[Jeff B] Oh, man. Ow?

There's a massive chunk of crystal

that just came out of her eye.

[theme music playing]

[theme music playing]

[narrator] In Dallas, a doll terrifies a young woman

as it appears to move by itself.

-[heels clicking] -[Holly] Oh, my God.

Oh, my God. Oh, my God.

[narrator] Kevin Kasky thinks this could be

a real-life house of horrors.

With so many different house invaders,

can we ever truly say that we are home alone?

[helicopter blades whirring]

[narrator] The Dallas Metro region

is in the middle of a rat epidemic.

These rodent intruders come in

looking for food and in exchange,

leaves some unwelcome deposits.

A little known fact about rodents

is that every time they take a step,

they leave a little drop of urine.

Glowing tracks along the floor

are likely urination paths of rodents.

So whether you see the urine or not,

it's there on your food.

And if they're infested, it could infest you.

[narrator] Rats' fleas, urine, and feces

can be loaded with vicious pathogens

such as the bacteria

that cause salmonella and typhus.

One of the most severe ailments

is Weil's disease.

Leptospirosis or Weil's disease

is caused by consuming rat urine.

This disease will cause feverish symptoms

and eventually attack your kidneys and liver.

If you've got vermin in your house,

you really want to get them out.

[narrator] Moving toys in a Dallas home

may not be a sign of a ghost,

but of a virus-carrying rodent.

Clicking doll heels should be the least of Holly's worries.

If we were aware of the diseases

that those pests carry,

we'd all pick the ghost.

[music box music playing]

[narrator] But with no reports

of a vermin infestation in the house,

some are convinced the house sitter

captured a paranormal event.

And there is nothing, so far,

to disprove the theory.

[narrator] Now, Fakiha,

a village in Northern Lebanon.

October 3rd, 1996,

a news crew films a stomach-churning sight.

[Jeff B] No, no, no, no.

No. Oh. Oh, man.

Ow.

There's a massive chunk of crystal

that just came out of her eye.

This is one of the most gruesome

human body phenomena I have ever seen.

[narrator] A 12-year-old girl,

Hasnah Mohamed Meselmani, sits calmly

as lumps of a clear crystal-like substance

come out of her eye.

How is that even possible?

[Raven] Oh. Oh, ooh.

That's crazy.

[narrator] Doctors are stumped

as these mysterious objects appear one by one

and fall from her eye socket.

[Ashanti] There's not just one.

There is another, and then another.

Are those diamonds falling from her eyes?

[narrator] The girl's father claims the fragments

are sharp enough to scratch the cover of a book.

The fact that these are so close to her eyeball

and could slice it open at any moment

makes me wanna puke.

What are these foreign fragments

and how are they coming from her eyes?

I've woken up with sand in my eyes before,

but this is insane.

[narrator] Hasnah's parents claim their daughter

has been shedding seven or eight clear crystals daily

for over six months.

[man speaking]

The family claims that this is a miracle.

It's a gift from God and that they're blessed.

For centuries, legends have talked about

how diamonds are the tears from gods

or the fragments of stars

that have fallen from the heavens.

But unless these are really actual diamonds,

it's hard to see how this is a blessing.

These crystals look like they're broken glass

or something with razor sharp edges

that just must be slicing her open.

[glass shatters]

[narrator] Getting glass in your face

can cause horrific injuries.

[indistinct radio chatter]

[narrator] In 2017 alone,

ordinary drinking glasses

caused more than 56,000 emergency room visits

in America.

Sometimes, the injury is deliberate.

-[glass shatters] -[indistinct shouting]

[narrator] In the UK,

assaults using drinking glasses

had been estimated to cost the health system

more than $3 billion a year.

[glass shatters]

[narrator] If this substance is broken glass,

the girl should be bleeding and in agony.

What kind of accident could this be

where shards of glass

are being removed from this girl's eye

with minimal injury?

There's something not right here.

[narrator] Biologist, Carin Bondar,

discovers a case in Brazil of a nursery school teacher,

who weeps weird solid objects.

These are soft as they form,

but they begin to harden up

as they're exposed to the air.

[narrator] The unfortunate woman's eyes

are more obviously inflamed than young Hasnah's.

But the strange tears share distinct similarities.

[Doctors have analyzed these tears

and found that they contain a large amount of keratin,

the same material in your fingernails.

So, in a way, this woman is crying fingernail tears.

[narrator] Medical experts believe the woman's corneas

are producing excess keratin

as an immune response to some kind of infection.

It must be like having sharp nails

gouged into your eye all day long.

It's got to be excruciating.

[narrator] Coming up.

Are these crystal tears a sign of organ damage?

A disorder like this is quite terrifying to look at.

And it must be equally terrifying to have.

[narrator] And is a deadly legendary monster

stalking Australia's rivers?

There's very few creatures that the aboriginals fear.

But this is one of them.

[theme music playing]

[theme music playing]

[narrator] A 12-year-old Lebanese school girl,

Hasnah Meselmani,

is seen weeping mysterious crystal tears.

Ashanti Davis suspects she could be suffering

from a disorder called cystinosis.

Cystinosis is a rare genetic disorder

caused by a mutation on a recessive gene.

It causes the build-up of an amino acid called cystine.

[baby cries]

[narrator] Around one in one hundred thousand infants

are born with cystinosis.

Crystals of cystine form inside cells

causing organ damage.

It first shows up in the kidneys

where it causes renal failure.

And then, it shows up in the eyes

where it creates a light sensitivity and blurriness.

[narrator] Crystals form in the cornea,

the outer window of the eye,

focusing more light directly onto the retina.

In England, a six-year-old boy

had such severe cystinosis,

his parents blacked out the windows of their home.

Can you imagine what it would be like

to have sunlight directed straight into your eye

every time you walked outside?

It would be agony.

[narrator] But physician, Siobhan Deshauer,

doubts it's cystine crystals

that we see coming out of Hasnah's eye the footage.

I don't think this is cystinosis

because it classically creates

these very small microscopic crystals...

[digital trilling]

...that you normally can't even see with the naked eye,

which makes me think something else

must be going on.

[narrator] A few months later, the girl's eyes stop shedding

the bizarre crystalline lumps.

Nobody seems to be able to explain

how or why these crystals get to be in her eyes.

This condition is somewhat terrifying to see

and it must be terrifying to have.

A serious medical problem,

a psychological response, or a clever trick?

Whatever it is, it can't be good.

[narrator] Now, the remote

Daintree River in the wet tropics

of Northern Queensland, Australia.

August 8th, 2017,

river tour guide, David White,

snatches footage of a beast he has never seen before.

I just notice this creature come up

out of the water.

I yelled to my partner,

"Oh, look at that. Look at that."

We were mystified by it.

It looked like a whale coming up

out of the ocean vertically,

and then going back down again,

sliding down to the depths.

[man] Oh, wow.

[laughs] Ooh, what?

[narrator] The mysterious mud monster

doesn't look like any known animal

on the continent.

I'm Australian and I've seen a lot of weird creatures,

but this one is something else.

[Kevin] It looked so weird.

Is it a head

or is it different part of the body?

It's like a predator waiting to ambush its prey.

[David] I've been working out here

on the river for 24 years

and this thing had us baffled.

Makes me shudder to think what's down below the surface?

What's the rest of it look like?

[narrator] Australia is a 2.9 million

square mile island,

almost the same size of United States,

but it has less than a tenth of the population.

The continent's isolated geographic location

in the vast southern oceans

has led evolution to spawn unique creatures

not seen anywhere else on earth.

Australia is definitely known

for some pretty crazy-looking animals,

but I've never seen anything like this.

[narrator] Re Monteith discovers

the inhabitants here have reported

a strange unidentified creature

lurking in the country's swamps and rivers

for centuries.

Aboriginal folklore

speaks of a terrifying swamp creature

called the bunyip.

[growling]

[Re] The bunyip grows up to 12 feet tall

with razor sharp teeth and a huge head.

Worst of all, it has a taste for humans.

[Karen] It would lay and wait in the swampy waters

and grab passers-by and pull them under the water.

What the descriptions all have in common

is the absolute dread

associated with this insidious creature.

[roaring]

[narrator] Some say it's an enormous star fish,

others a large walrus-like beast

with tusks and flippers.

Historian Karen Bellinger

considers that the bunyip could be a creature

that used to inhabit this continent in huge numbers.

This part of Australia in Queensland

has, for a million years,

actually been host to a crazy variety of animals

that are not found anywhere else.

[narrator] Archeologists have found Australia

was once the land of giants.

Just 50,000 years ago,

in the Pleistocene Era,

mega beasts ruled the continent.

-[screeching] -[narrator] Dromornis,

a giant 9-foot tall goose

with a skull-crushing beak.

Megalania, a 16-foot long

fresh shredding reptile.

The largest land lizard the world has seen

since the dinosaurs.

And marsupial lions,

a tree climbing terror

with teeth like sword blades.

It resembled a Tasmanian devil,

just 10 times bigger.

Aboriginal cave paintings

depict a terrifying primordial landscape

teeming with enormous creatures.

What these depictions of fearsome Pleistocene animals

brings to mind immediately is the question of,

how they coexisted with the humans.

Were the humans the hunters or the hunted?

[narrator] Coming up.

Is this an undiscovered prehistoric creature

hiding out in the Australian wilderness?

If I were to encounter a Diprotodon,

I would try to run as fast as humanly possible.

[static noise]

[narrator] And is a vigilante super hero

cutting a blaze through the streets of Florida?

God Almighty, what the heck is that?

[static noise]

[narrator] On the banks of the remote Daintree River

in northern Australia, a local wildlife guide

films a mysterious monster emerging from the mud.

Whatever this thing is, it sure doesn't like people.

[narrator] Aboriginal people have pointed

to skeletal remains of one creature in particular

and referred to it as a bunyip.

Accounts suggest that the bunyip

is actually rooted in a real animal

that is documented archaeologically in Australia.

[narrator] The Diprotodon.

This terrifying beast could grow to 12 feet long

and weigh around 6,000 pounds.

Heavier than most modern rhinoceros.

It's easily the largest marsupial ever discovered.

If I were to encounter a Diprotodon,

I would try to run as fast as humanly possible.

The fossil records suggest that most, if not,

all of these megafauna died out 40,000 years ago.

[narrator] But could a descendant

of one these beasts survive, hidden deep

in the unexplored swamps and rivers?

There had been recent reported sightings

of other Australian mega mammals

thought to be long dead.

The thylacine, an Australian wolf-like marsupial

that first evolved millions of years ago,

was believed to be extinct.

But in 2016, Australian wild life trackers

in Tasmania catch footage of what looks like

a surviving specimen of the creature.

The Australian continent is so vast and wild

and some in respects, largely unexplored.

Anything really is possible.

[narrator] Perhaps the Diprotodon

is hiding in the swamps of the Daintree River.

Every year in Australia, thousands of people

go missing and many are never seen again.

We usually think that this is because

of the salt water crocodiles, so it's really scary to think

that there could be a creature that is as yet undiscovered

that lives in these waters

and can drag people to their deaths.

[static noises]

[narrator] Now, southern Florida.

[digital trilling]

[narrator] October 24th, 1999,

2:10 AM,

a police helicopter camera films a huge ball of light

streaking along the highway,

flashing past other vehicle on the road.

God Almighty, what the heck is that?

This thing is so bright it looks like a shooting star.

It appears to be moving at a very high rate of speed.

[Rachel] There's no way that's normal.

It's like a speeding fire ball.

[narrator] The chopper races to catch up

with the fast-moving flaming orb.

This is a thermal camera, so brightness equals heat.

This is not normal.

The heat and the light that this is giving off

is very intense.

What is this thing that's sort of flaming

its way down the highway?

How are you gonna stop it?

[static noise]

[narrator] As the footage progresses,

engineer, Nick Householder thinks

he is able to identify the object.

As this fireball flies down the road,

it kind of comes into more focus.

And you can start to see something

that looks like a car.

[narrator] But this doesn't appear

to be your average sedan.

A normal car engine might put out something

like 200 degrees Fahrenheit. It's pretty hot.

But this thing must be putting out

many hundreds more, if not, thousands more degrees.

[helicopter rotor whirring]

This car is glowing so much,

it's even lighting up all the cars around it.

I think the heat signature this intense

could be a sign of a jet engine.

[engine roaring]

[narrator] Engineers have been strapping

jet engines to cars for more than half a century.

The fastest jet car can achieve speeds

in excess of 763 miles per hour,

breaking the sound barrier.

[whizzing]

[narrator] To increase thrust by an extra 50%,

add an after burner.

This injects fuel into the exhaust stream

and will produce some impressive flames.

[whizzing]

[narrator] This souped-up Chevy Lumina

is capable of doing zero to three hundred miles

per hour in under six seconds.

[whizzing]

[narrator] But like all jet cars,

it's illegal to operate on the highway.

A jet-powered car racing through night time streets,

it sounds like a comic book.

[indistinct radio chatter]

But maybe that's what's going on here,

maybe this is some kind

of nighttime vigilante justice seeker.

[suspenseful music playing]

[narrator] Comic book superhero crime fighters,

armed with gadgets and special powers

have never been more popular.

Most superhero fans stick to reading the books,

collecting the toys, and watching the movies.

But some take it one step further.

There is an uptick in the United States of, like,

real-life vigilante "caped crusaders"

going out and attempting to fight crime.

You've got to think.

What kind of person would go through

all of that trouble and why?

How about Seattle's Phoenix Jones?

He travels around spraying people with mace

to break up fights. Well, what does he get for it?

Things like getting kicked in the face

and a broken nose.

After I got stabbed the first time,

I got some stab protective gear.

Then, when I got shot, I got a bulletproof vest.

You might think this is funny,

these guys taking their cues from comic book heroes, uh,

but it's not so funny to the police.

The outfit's capabilities are pretty awesome.

I've got D3O material, which is a material

that gets hard when you punch it.

I've got a phaZZer.

It shoots two prongs that electrocute people

and drop them.

It's also got a rubber ball shooter

and tracking links.

[narrator] For any determined superhero wannabe,

a cool crime fighting suit might not be enough.

They need their own Batmobile to chase down the bad guys.

Although vigilante activity is both

highly dangerous and often illegal,

Phoenix Jones is not alone.

Other real life superhero groups

operate in cities across America.

There's Fallen Boy, and the Grim in San Diego,

Master Legend in the Littlerock,

and Neuromyth in New York.

On this night, did crime-ridden Florida

have its own vigilante superhero?

It's not completely impossible

that somebody figures,

"Okay,2:00 AM. Cops are asleep.

I'm just gonna take my jet-powered Batmobile

out on to the road and fire it up."

It would probably look a lot like this

on a thermal camera.

[indistinct radio chatter]

[static noise]

[narrator] Engineer Brian Wolshon

suspects the extreme heat signature

is evidence of an unfolding disaster

and the driver is in imminent danger.

Seeing this type of sustained heat signature

suggests to me that this vehicle

might actually be on fire.

Vehicles are loaded with materials

that can catch fire and burn.

We have plastics, upholstery, lubricants,

and of course, fuel. All of those can burn.

[narrator] In 2019, there were around

a hundred ninety thousand highway vehicle fires

in the US alone.

Five hundred and fifty people were killed.

So once this fire start to burn,

it can cause releases of toxic chemicals

within the passenger compartment.

Within seconds, the entire vehicle

can become engulfed in flames.

So, if a vehicle catches fire,

you need to pull over, stop, and get out.

[narrator] But this driver isn't slowing down.

In fact, he seems determined to keep going.

[Nick] This is terrifying to watch.

It looks like the entire underside

of the car is on fire now.

[static noise]

[narrator] Explosives professional,

Matt Kutcher has spent over 20 years

as one of Hollywood's top pyrotechnics experts.

He believes this can't be a gas tank fire

as the car would have ground to a halt.

[Matt] As you can see in the footage, it's very hot.

And since it's probably not the gas tank,

it would have to be something else.

Another source of fuel, if you will.

And the best source of that is tires.

So, if you're looking at something like 30 pounds

of tire, that's a lot of rubber,

that's a lot of fuel.

I wonder if the vehicle was under pursuit

and maybe they used one those spike strips.

[narrator] Spike strips are used to immobilize

the targeted vehicle by puncturing its tires.

Flat tires make get away driving almost impossible

as they quickly disintegrate and ultimately catch fire.

If the tires went flat and they're flapping around,

maybe that's what caused the tires to catch fire.

I think we go get ourselves a car,

light the tires on fire, and see if we can't get

the heat signature to match what we see on that video.

[helicopter whirring]

[static noise]

[narrator] Coming up.

Kutcher puts the tire fire theory to the test.

Matthew, you light the tire.

Rolling hot stuff.

[machine whirring]

[narrator] And sinister vibrations from underground.

This weird sound could actually be

the last sound that he ever hears.

[static noise]

[narrator] In Florida, a camera catches

a red hot car speeding down the freeway.

Hollywood special effects expert Matt Kutcher

believes the car's tires might be on fire.

To test the idea, Matt and his team

are using an old SUV drained of gas

and stripped of combustibles.

They set up a pulley to safely tow the car

using an endless cable loop.

This is a system we've used many times

while making motion pictures to pull cars.

You know, whether the cars are on flames

or whether we're gonna blow them up.

So, I know with high degree of certainty

this is gonna be a really safe method

to pull a car with flaming tires.

[narrator] The team uses Hollywood special effects

techniques to ignite the tires.

What we're adding to it is a little extra energy.

A little extra va-va-voom.

[narrator] Matt's movie magic will speed up the process

of the tires catching fire, simulating the effect

of the car's brakes overheating

or driving after punctures from a police spike trap.

[hissing]

All right. Everybody standby.

Matthew, light the tire.

We're gonna get the car rolling,

film it with our infrared camera,

and see if we can get a comparable shot

between our car and the car we see on the video.

Yeah, a little rolling hot stuff.

Rolling hot stuff.

[narrator] Camera readings indicate the heat

from the flaming tires is intense,

reaching hundreds of degrees.

We're not in a high speed chase,

but I do think if you scaled it up,

I think we're onto something.

I mean, look right there. You see all the...

How it's white?

I think it's a good experiment.

I think the one that we got here

definitely shows the same heat signature.

[suspenseful music playing]

[narrator] It's clear to Craig Gottlieb

that the driver is not planning on stopping

even though he's in serious danger

because he's being chased by the cops.

[Craig] This is a police pursuit.

This guy is trying to evade capture

and he's probably pushing his vehicle to the limit.

You can see that this guy will do anything

to avoid being caught.

[narrator] As the tires reach 750 degrees Fahrenheit,

they ignite and start to disintegrate.

[Brian] I see flames coming out.

I see sparks out of the back.

It almost looks like this whole thing

is ready to explode.

[narrator] The car now seems to be rolling

on its metal rims.

The heat seems to be spreading forward in the car,

enveloping more and more of it.

The vehicle is just coming apart at the seams.

To drive like this, you have to be a madman

or seriously bad dude.

[Nick] This is terrifying to watch.

The only thing I can think is that

we are seconds from an explosion.

[narrator] Finally, the desperate crook

makes a run for it on foot.

They knew that they were on fire

but it's like they were saying to themselves,

"I'm gonna keep going because if they catch me,

I'm done."

[narrator] Patrol cars cut off his escape

and an officer tackles the fleeing man.

It's the end of the road for the driver

of the Florida freeway fireball.

You can outrun a patrol vehicle,

but you can't outrun a helicopter.

[static noise]

[narrator] Now, for Vejle, a small town

on the island of Zealand, Denmark.

[digital trilling]

[narrator] October 7th, 2020 Kispa Newlan

hears a mysterious rhythmic noise in his backyard.

When he investigates,

it appears to be coming from under the ground.

If I go out in my backyard and it's making noises

and shaking like that, I'm not okay with that.

Seeing the earth vibrate like that

is not natural.

There's absolutely something weird going on.

It's beating, it's causing vibrations.

It's making a lot of noise.

It's hard to tell if it's a natural occurrence

or if it's something mechanical.

[narrator] When Newlan starts digging,

the mystery deepens.

[Craig] The deeper he digs, the louder it gets.

So, either he's getting closer to it

or it's getting closer to him.

You can see the ground physically shaking.

What could possibly be down there

making all that noise and why can't we see it?

[static noise]

[narrator] Author Jeff Belanger

finds stories of weird underground chambers

beneath Denmark going back over a thousand years.

Beowulf is this epic tale from the Dark Ages

where Beowulf battles these various beasts.

The worst of which is Grendel

who lives in these vast underground caverns.

Grendel is a fearsome half man,

half beast, who is terrorizing

King Hrothgar's feasting hall at Lejre.

Grendel kills and eats King Hrothgar's men,

and then retreats to his underground lair.

Beowulf has to travel into these caverns

to fight Grendel and his mother.

[Grendel growling]

When you hear the ground rumble and shake,

it's easy to see why people might think

that an ancient creature is stirring.

[static noise]

[narrator] Coming up.

Does this man have something sinister in his soil?

The temptation is to keep digging,

but you might not like what you find.

[static noise]

[narrator] In Zealand, Denmark,

a man is spooked by a strange noise

and eerie vibrations

coming from under his backyard.

Historian Craig Gottlieb discovers

Denmark is crisscrossed by a labyrinth

of secret manmade tunnels.

Declassified documents show that the Danish government

did in fact build lots of underground tunnels

and bunkers during the Cold War.

Take for example, Stevnsfortet.

Sixty feet deep, one mile long,

it's a tunnel system built to monitor Soviet activity.

[narrator] In the 20th century,

Denmark was on the front line of the Cold War.

[announcer] Denmark has been the traditional gatekeeper

of the Baltic.

[narrator] Any Soviet ship trying to get

to the Atlantic quickly has to pass

within a few miles of the Danish coast.

The role of gatekeeper puts the entire nation

in the crosshairs of the nuclear superpower.

Declassified Soviet battle plans

reveal how in the event of an attack,

the invaders would devastate Denmark

with dozens of tactical nuclear weapons

before landing troops on Zealand.

To protect its people from nuclear holocaust,

the Danish government digs 2,000 fallout shelters.

[Craig] Another state secret.

Regan Vest, built in Northern Denmark

in the 1960s to protect the royal family

and the government in case of nuclear war.

60,000 square feet, 230 rooms, it can house over 300 people.

This place is massive.

[narrator] Patrick Tomlinson discovers that former

top secret Cold War bunkers are now being monetized

by 21st century tech firms.

Denmark has extensive underground facilities

and sometimes, they're used for server farms.

Is that what we're seeing here?

[narrator] The cool consistent temperatures

in these 20th century silos and the high security

which comes with them is perfect

for this 21st century application.

In Montgomery, Texas, a 40,000 square foot

nuclear bomb shelter now houses

a state of the art data center.

[upbeat music playing]

[narrator] Protected by a 16-inch steel door,

submarine engines provide power

to the network operation center

of one of the country's internet service providers.

And in Butler County, Western Pennsylvania,

a data center sits more than 200 feet

down in a former limestone mine.

The 200 acre campus is protected

by armed guards and booby traps.

Much of the information we all think of

as stored in the cloud is actually hosted

deep beneath the earth.

But engineer, Nick Householder,

doubts the mystery sound is coming from a tech bunker.

Underground complexes are typically placed

many tens of feet below the ground

to gain the natural protection of the rock above.

[rumbling]

These vibrations seem to be occurring

very close to the surface which maybe discounts the idea

of something occurring deep underground below.

This must be some kind of surface-level phenomenon.

But the question is, what?

[narrator] Householder listens to the noise

and believes this could be

some kind of excavation device.

The vibrations we're observing

seem to be happening in a very rhythmic way.

This reminds me of a mechanical

drilling machine of some kind.

[narrator] The backyard disturbance could be evidence

of an engineering technique

known as horizontal directional drilling.

You effectively have a drill head on a long line.

[machine whirring]

[Nick] The clever part is that you're capable

of stealing the drill head from afar.

Oftentimes, magnetic sensors

allow the operator to tell where the drill head is,

but that doesn't tell them

what they're drilling through.

It sounds like a useful invention.

But if it goes wrong, it goes really wrong.

[narrator] Sometimes, the drills cross-bore

cutting through other utilities.

The results can be catastrophic.

[narrator] 2013, Kansas City.

A horizontal drilling operation hits a gas line.

The resulting explosion destroys a restaurant

killing one person and injuring 15 others.

The idea that people are messing

with the earth underneath you and you are helpless

to do anything is really disturbing.

[narrator] In Denmark, Newlan's backyard dig

hits pay dirt.

He unearths a drill,

boring through under his garden.

And the sharp spinning bit

was just inches below his lawn.

If that directional drill comes out right now,

the results could be disastrous.

Can you imagine being impaled by a giant drill?

Not a way to go.

This weird sound could actually be

the last sound that he ever hears.