Original subtitles

[narrator] Worldwide, 45 billion cameras record

our daily lives in our hands,

in our cars and in our homes.

They capture things that defy explanation.

What the heck is going on here?

[man 1] Check this out.

[narrator] Experts carry out forensic analysis

of these unusual events.

Wow. Now, that's a cracker.

Ohh!

This doesn't make any sense.

There has to be another explanation.

So, what could it be?

[narrator] Coming up,

the legend of a lost atomic bomb

on the roof of the world.

It's like retina burning bright.

It's like looking directly at the sun.

[George] Is it possible that this mountainside explosion

is somehow related to one of these

lost chunks of plutonium in the Himalayas.

[narrator] In California...

Oh, my God!

[narrator] ...what lies beneath the suburban front yard?

I mean, how far down did this kid go?

[narrator] And as China advances in the space race...

There's a weird column of light up in the sky.

[Tim] Well, we're looking at some sort of portal,

things we've never seen that we read about in science fiction.

[narrator] Bizarre phenomenon...

Oh, my God!

[narrator] ...mysteries caught on camera.

This is just mind-boggling.

[narrator] What's the truth behind this?

Strange Evidence.

Now, Uttarakhand, Northern India.

2020,

a villager captures a moment of horror.

My goodness.

[whistles]

It's huge.

And it looks...

it looks worrying.

[narrator] It's as though a second sun

has burst out of the mountain.

It is pulsing, is pulsating out

from this sort of central kind of fire.

And there's this amazing sort of blazing white light.

It's like nothing I've ever seen before.

It's like retina-burning bright.

It's like looking directly at the sun.

[narrator] Locals are terrified

as the mysterious explosion angrily intensifies.

I would not be standing there.

I am out, y'all. Time to go.

[David] You got to ask yourself,

"What the heck is going on here?"

[narrator] The location of the blast

reminds journalist Amy Shira Teitel

of one of the Himalayas most terrifying mysteries.

Not the Yeti or the Lost City of Shangri-La,

but a 1965 Cold War spy mission

that went disastrously wrong.

India teamed up with the United States

to erect these monitoring posts in the Himalayas

to keep an eye on what was going on with China.

[narrator] This was a time of high tension.

China, just a year earlier,

had tested its first nuclear weapon,

and the West was anxious to prevent a surprise attack.

[George] These instruments were designed to detect

any nuclear activity across the mountain range in China.

But these instruments had to be powered by something,

and in this case, plutonium.

[narrator] In October 1965, a team of climbers

haul a 125 pounds of plutonium-powered kit up mountain Nanda Devi,

the second highest mountain in India.

[George] This is an insane plan.

The peak is over 25,000 feet.

How that idea went from someone's brain to actually becoming

a thing is mind-boggling.

But this is the Cold War.

Extreme measures were taken.

[narrator] Plutonium is a great substance for powering equipment,

but it's one of the most dangerous elements on earth.

Tiny plutonium particles,

if released large in the lungs can destroy the cells

inside the body, leading to cancer and lung disease.

And just hours into the dangerous expedition, disaster strikes.

[Craig] And then what happens? Surprise. A blizzard hits.

[George] And in order to save themselves,

they had to abandon all of their equipment

at high altitude on a ledge, including the plutonium.

When the team returned the next spring,

they went to go find it...

and it was nowhere to be seen.

[narrator] The lost plutonium is now a ticking time bomb.

[Craig] So, since the 1960s, villagers believe firmly

that these devices are still out there buried in the snow.

[narrator] Then in February 2021,

a glacier on Nanda Devi breaks away.

The valleys below flood with meltwater carrying rocks

and other material down from the peak.

Could these plutonium batteries have been carried with melting snow,

and could they have then reacted somehow, 60 years later?

[narrator] But electrical engineer David Wallace

believes that while these plutonium batteries are a deadly menace,

they wouldn't erupt with the ferocity seen in the video.

You know, there are various types of plutonium.

Now, you have the very explosive ones that you use in bombs,

you have ones that you use in the nuclear power plant,

and then you have the different type of plutonium,

the isotopes which are used in batteries.

Now these battery isotopes are going to be

very much less volatile and would not generate

the explosion like you would see in this video.

That leads us to think, okay,

there is something else going on here.

[narrator] Wallace thinks the blazing ball of light

may be a result of India's reliance

on the dangerous slopes of the Himalayas for its power.

[David] You notice that the weather is not good.

Very cloudy.

It looks like it's a heavy rain,

possibly hail falling down in the area.

If you have power lines getting blown around by the wind,

where you have the voltage flowing through it,

you can have the possibility

of the two lines touching each other,

and when they do, they create an electrical arc

leading to catastrophic failure.

Any time you have an electrical power line

that gets broken,

that electricity sort of has to go somewhere

and it tends to arc, and spark.

[narrator] Wallace wants to investigate

if a power line arc could have caused the explosion in the clip.

He constructs two replica power lines in order to see

if he can produce an electrical arc.

What we have here is a rod

that is going to be mimicking a transmission line

or a high voltage line.

[narrator] This hot stick will represent the other transmission line.

When Wallace touches the rod with the hot stick,

he will generate a surge of 40,000 volts of electricity.

[David] So in a moment, I will take the hot stick and approach the line.

And you should draw an arc between these two and we'll see what happens.

All right. Lights off.

[narrator] Wallace uses a smoke machine

to recreate the cloudy conditions in the clip.

All right.

Here we go.

[narrator] Coming up,

did a landslide create an electric apocalypse?

[David] You got to understand, this is extremely dangerous.

[narrator] And in California,

a deadly secret beneath an ordinary front yard.

[Tylor] Kid just falls straight through it.

And... and... and you wonder what... what's happened here?

What... what's going on?

[narrator] In the Himalayas, a man films a bizarre ball of light

blazing above his village.

Electrical engineer, David Wallace,

thinks a power line arc may be to blame.

He has set up an experiment

to see if the color of an arc matches the blinding light in the footage.

Here we go.

So, here we have around 40,000 volts of electricity

jumping through the air through my stick.

That 40,000 volts is enough to kill you on the spot.

[narrator] Wallace doesn't produce an explosion,

but does create an electrical arc

with similar colors to the blast in the footage.

So now, granted, what we have demonstrated here

is nowhere near the size of the arc

that we saw on the video from India.

Now, we also have to understand that on my set up,

I'm running about 40,000 volts.

In India, a transmission line can carry anywhere

from 115 to 500,000 volts.

And you may have thousands of amps.

If you get an arc in these conditions,

it's going to be tremendous.

It's going to be huge.

It's enough to actually melt the metal.

So, we demonstrated what we saw, but in a much smaller scale.

[narrator] Electricity lines cross the Himalayas.

India has a population of over 1.4 billion people

and their energy needs mean valleys

have to be dammed high in the mountains.

Over 30% of India's thermal power

and 52% of hydropower comes down from the Himalayas.

And India is not necessarily known

for their first class power grid.

[narrator] Uttarakhand, where this video was shot,

had 972 landslides in 2020

and experiences over 3,700 extreme weather events every year,

which destroy the delicate wires and poles

that contain huge amounts of raw power.

Scientists at NASA estimate that thanks to climate change,

landslides in Himalayan regions

will increase by up to 70% before the end of the century.

More of these lethal power blasts are inevitable.

[Linda] The power arc on the scale

that we're seeing in this video

would have been incredibly hot and incredibly bright.

I certainly hope that no one was nearby

when this happened

because something like that on that kind of scale,

that would be incredibly dangerous.

[narrator] Now, Southern California.

September 24th, 2021, 4:28 p.m.

A security camera films as two brothers,

play in the front yard of their family home.

They're playing catch or they're playing with the ball, I think.

And it looks like there's a dad and maybe a little sister.

[narrator] One of the boys seems to discover

something mysterious on the ground.

His brother soon follows.

Two of them gathered together.

They seem to be testing it or probing it in some way.

[narrator] And then...

[Dean screaming]

Oh, my God!

He went straight down into it.

The kid just drops.

I mean that poor father.

[narrator] Tyler Bloss, the boy's father,

desperately tries to rescue his son,

while his daughter screams in terror.

My son just disappeared into the ground.

I mean, how far down did this kid go?

[Tyler] I tried to reach down to see if I could reach him.

I wasn't sure if I'd be able to.

[Jeff] The kid just falls straight through it like he was not even there.

It's almost invisible.

And... and you wonder what... what's happened here?

You know, what's going on?

[narrator] Engineer Brian Wolshon

believes this boy hasn't fallen into a sinkhole or a cavern,

but some kind of deliberately constructed underground space.

What I'm seeing here is the hole that opens is very round.

It's very uniform.

So it looks like it's not something

that is a naturally occurring hole.

[George] It looks as though he may have broken

through some secret underground tunnel.

[narrator] And Southern California is notorious

for its secret tunnels created by criminals

to bring misery to the United States.

Many times these tunnels are used to transport people.

However, these tunnels were constructed

in the first place to transport drugs across the border.

[narrator] United States border protection

have discovered over 200 illicit tunnels

beneath the US-Mexico border since 2003.

[George] About 90% of the cocaine

that gets smuggled into the US every year

comes from Colombia via Mexico.

And one of the most efficient ways to smuggle drugs

from Mexico to the US is underground

through a series of interconnected tunnels.

[narrator] Many of these passageways

are the work of one man, Joaquin "El Chapo" Guzman.

[George] El Chapo was the king of the tunnels.

His tunnels were next level.

We're not talking just digging in the dirt with a shovel.

Oh, no.

His tunnels could avoid ground penetrating radar

from police by being 70 feet or more underground.

Some of them had various hydraulically controlled trap doors.

Like, this was sophisticated.

[narrator] US authorities are astounded

by the engineering prowess of El Chapo's million dollar tunnels

featuring arched ceilings that help distribute

the pressure of the Earth above to prevent collapse.

One official actually described them

as something out of a James Bond movie.

[narrator] Most drug tunnels are built by slave laborers,

ordinary Mexican men tricked into backbreaking

underground labor for months at a time.

Digging is said to move at a speed of just 16 feet a day.

After the tunnel is finished.

The workers are often shot.

In January 2020,

US border guards uncover the longest suspected

drug tunnel ever found between the two countries

emerging here in Southern California.

It went from Tijuana, Mexico,

and extended 4300 feet into a warehouse in San Diego.

But it wasn't just a tunnel.

It had an electric rail system.

It had air vents.

It had drainage.

The authorities have likely only found

a fraction of the tunnels that are actually out there.

Who knows how many are buried under the desert?

[narrator] But former CIA agent Tracy Walder is unconvinced.

[Tracy] The entrances to these tunnels

were typically very well concealed.

They would usually be inside of a warehouse

or inside of a private home.

They wouldn't typically be in the front yard of a private residence.

[Dean screaming]

[Tracy] I just don't think that

that's what we're looking at here.

[narrator] Coming up,

what's lurking in this front yard deathtrap?

You, of course, could drown.

But there's also the risk of bacterial infection.

You can asphyxiate, because it's a low oxygen environment.

[narrator] And a city comes to a halt as a portal seems to open above it.

[Craig] This is... There's clearly something there.

But what is it that

they're staring at up in the sky?

[narrator] In California, a home security camera

captures the moment a young boy is swallowed

by a strange hole in the ground.

Science journalist, Jeff Wise,

notices the ground's movement just before the collapse.

There's this kind of a softness or a,

a yielding of the surface.

It's not the terra firma, the hard,

solid earth that it looks like.

[narrator] This could be a death trap

that's lurking in millions of American yards.

So, it might be that what happened,

this kid was jumping up and down

on the surface or the hatch

to an old abandoned septic tank.

[Brian] So, in simple terms,

we can think of a septic system

as a series of large concrete boxes

that basically take the outflow

of wastewater from a home

and let things separate and filter out.

[George] Before a lot of these houses

were connected to the actual sewer systems of the city.

Many people had septic tanks.

Many of those septic tanks were abandoned,

just left to sit,

because it's expensive to extract these things

and pull them out of the ground.

So, it's certainly not out of the question.

There could be an abandoned septic system

in someone's front yard.

[narrator] With a septic tank.

It's not the fall that kills you.

It's the contents padding your soft landing.

[George] You, of course, could drown.

But there's also the risk of bacterial infection.

You can asphyxiate,

because it's a low oxygen environment.

[narrator] In Texas in 2004,

a two-year-old girl is killed

when she falls into an abandoned septic tank

just a few feet from her home.

The same week in New Jersey,

a 92-year-old woman dies after plunging 15 feet

into a cesspit behind her house.

These deadly hidden holes are common in the United States.

Sanitation experts believe there could be

up to 60 million abandoned septic tanks

buried in the backyards of homes across the country.

Each one could be a disgusting and deadly trap.

[Jeff] The kid, fortunately, seems unharmed.

He was lucky.

[Dean] When my dad pulled me out of the hole,

I felt like relieved

that I wasn't in there anymore,

because I was freaking out.

Like I'm in a hole and I don't know what's happening.

[Tyler] We were completely shocked to find the hole,

I guess, advice I would give to other homeowners

purchasing homes would be to make sure

you get a septic inspection if you have a septic system.

[Dean screaming]

It could have been disastrous.

We're... we're so thankful,

everything worked out the way it did

and we're grateful that he...

he didn't have a scratch on him.

It's a miracle.

[narrator] Now Shenyang, China.

September 8th, 2021...

early evening.

Commuters heading home stop in their tracks

to film an eerie sight

towering above them in the sky.

What is this?

[Chad] I have no idea.

I'm not sure what we're looking at.

[Tim] Yeah. I mean, this... this looks like

something out of a science fiction movie.

There's a weird column of light up in the sky.

[narrator] Whatever it is,

appears to have bright tentacles bursting from its core.

[George] You know, this is fascinating.

It looks like there's this giant luminous jellyfish

in the sky over China.

And it almost has a look of a glowing staircase

that leads up into the heavens.

[Chad] This is... There's clearly something there.

But what is it that they're staring at up in the sky?

[narrator] Physicist Chad Orzel wonders

if this could be a Chinese attempt to create a door between realities.

[Chad] When it's zoomed in,

it looks kind of like a hole in the sky,

like some, some sort of gateway to somewhere else.

[Tim] Are we looking at some sort of portal?

Things we've never seen that we read about in science fiction.

[narrator] China is competing with America in a new space race.

In 2021, it successfully landed a rover on Mars.

But China's ambitions appear to go beyond

mere conventional rockets as a way of journeying into the cosmos.

They appear to be harnessing quantum physics.

There are a lot of physicists

they really believe these are not just whacko ideas,

but they're real science that can explain

how something could get across

the universe very quickly.

[narrator] In 2017, China makes an announcement that,

if true, shakes the foundations of reality.

It says one of its satellites

successfully beams pairs of entangled photons

to two separate locations

more than 700 miles apart down on Earth.

These photons appear to exchange information instantaneously,

faster than the speed of light.

It could be the first step towards a doorway

from one point in the universe to another.

The holy grail of intergalactic travel.

[Michio] There could be a shortcut through space and time,

allowing you to go faster than the speed of light.

Take a sheet of paper...

Take a sheet of paper and fold it,

and fold it such that two points come together.

Two distant points on the sheet of paper

are now folded together into one,

so that if you were to go through the fold,

you would instantly wind up on the other side of the universe.

That's what a gateway, a wormhole, would look like.

[narrator] The fastest American rocket

would take 73,000 years

to reach planets orbiting our nearest foreign star,

Proxima Centauri.

Chinese astronauts beamed through a wormhole

could arrive on other worlds instantly,

colonizing the galaxy in a human lifespan.

[Tim] And the scary part is we don't know

what they're doing.

And I guarantee you it's not going to be in some report in Scientific American.

It's going to be hidden for a long time.

We may not know it until it's too late.

[narrator] But if a Chinese laboratory

was unleashing a wormhole, it'd be incredibly dangerous

to deploy it in the middle of a city.

[Chad] The kind of energy you need to create a wormhole

would require a particle accelerator

that's vastly bigger than anything

we've ever built on Earth.

So these wormholes are a staple of science fiction travel,

but they're well beyond anything our civilization

can hope to do at this point.

[narrator] Coming up, is this weird column of light,

a portent of danger for the people of Shenyang?

People suffer from heart disease,

lung cancer, strokes and even neurological disorders.

[narrator] And in the Philippines,

a hairy horror on a beach in paradise.

Oh, wow... Whoa.

[narrator] In Shenyang, China,

a man films a mysterious ladder of light

leading to a bizarre plume.

Engineer Brian Wolshon finds a threat

in the city's atmosphere that could explain this bizarre vision.

Historically, Shenyang has had some of the highest levels

of pollution measured anywhere in China.

[narrator] Pollution readings in the city have soared

to 50 times the safe limit.

Residents can breathe in up to 1400 micrograms

of fine particulate matter a day,

the equivalent of smoking 60 cigarettes.

And the pollution produced by this fossil fuel-chugging city

kills at least 16,000 people a year.

One of the biggest contributors

to air pollution here is coal.

This part of China relies heavily on coal

for industrial purposes and home heating systems.

And when coal smoke gets into the air

and people are exposed to fine particulates over long periods of time,

they can develop some serious health problems.

People suffer from heart disease,

lung cancer, strokes and even neurological disorders.

[narrator] This sinister smog can reduce visibility levels

to just 300 feet and has an eerie effect

on Shenyang's buildings,

as it shrouds them in thick, toxic clouds.

The air in Shenyang it's so thick was smog

that at times buildings become obscured to the point

where even the neon signs

that are attached to the facades

look as though they're suspended,

almost levitating in mid-air.

Maybe the apparition that we're seeing in this clip

is some sort of distortion in the atmosphere

that's caused by these very high levels of pollution.

[narrator] But science journalist Sarah Cruddas believes

this weird effect could have been caused

by a rare break in the smog that saturates the city.

We've got thick cloud and then we've got some

breaks in the cloud and perhaps the...

the sun is just at the right place,

so, it's actually reflecting light on this building below.

And then you've got the light shining through

and it's basically a hole in the cloud,

which looks incredible.

And then by sheer coincidence,

it's perfectly aligned with this high rise building.

If you were a few blocks to the left

or a few blocks to the right,

all of these elements would never have combined

exactly perfectly the way we're seeing here.

We spent much of our lives looking straight ahead,

but it really does pay off from time to time

to look up to the skies,

because every now and then we're treated

to a beautiful spectacle of nature.

[narrator] Now, Siargao Island, the Philippines.

January 26, 2021.

It's late evening.

A group of fishermen are heading home

when they film a bizarre body on the beach.

[people speaking in foreign language]

Oh! Woah!

Oh. Wow! It's pretty big.

Oh! What is that?

[narrator] These men are used to finding all kinds of sea creatures,

but this is like nothing they've ever seen before.

It looks like a carcass.

You can see what clearly look like ribs.

And the part they're specifically poking

with the stick appears to maybe be the skullcap.

[narrator] It's jet black,

even its bones, though it isn't burned.

And even stranger,

the men spot something clinging to what remains of its skin.

These local fishermen noticed that something's not quite right.

There's something on it that looks like hair.

[people speaking in foreign language]

[Eric] I can't understand what they're saying,

but I can understand that they're saying "What?"

What exactly is this? What are we looking at?

[narrator] Coming up, is this beastly body of warning sign

of a massive earthquake.

[Dustin] It's got to be something extraordinary

to bring a creature

from the deep sea up to the shore.

[narrator] And on an English hillside,

a boy films four ghostly white figures.

What the hell is that?

In Britain, this is where they keep the criminally insane.

[narrator] In the Philippines,

fishermen discover the remains of a strange sea creature.

What is all over this animal?

Is that something natural occurring or something unnatural?

[narrator] Marine biologist Eric Hovland

believes the black coloring may be a stain from a terrible accident.

The blackening.

It reminds me of the animals that get caught in an oil spill.

Could this have been the fate of this creature as well?

Unfortunately, large scale oil spills

are relatively common in and around the Philippines.

In 2006, an oil tanker sunk off the coast

of the Philippines during a violent storm,

releasing half a million liters of fuel into the water.

It was the worst spill

in the history of the Philippines as yet recorded.

[narrator] Thick black sludge smothers over a 100 miles of coastline,

killing thousands of marine animals in the area.

And the Filipino government makes a bizarre plea

to the public after this spill,

a plea that could explain this beast's weirdest feature.

The government asked people to help by sending their hair

and they bring it together into these booms

to sort of help keep the oil

in one place until they can suck it up.

It seems crazy, but human hair actually absorbs oil really well.

So obviously, hair salons are a great place to get this hair from, right?

So they sweep it up off the floor

and send it off to help with the oil slick,

but also prisoners.

And I'm not sure if they had much say in the matter.

So, going back to the video,

could this be the result of the oil spill

and its subsequent cleanup?

[narrator] But zoologist Roland Kays

sees other creatures on this carcass that could rule out an oil spill.

[Roland] The thing is, when fish get covered in oil,

they're kind of preserved.

You don't see maggots eating oil infected fish

and you see maggots on this thing.

So, I'm thinking maybe it's not from an oil spill.

[narrator] Biologist Kelly Price

suspects this mysterious marine creature

could come from a deep sea dwelling species

rarely seen by humans.

[Kelly] So, what this could be is an anglerfish.

Anglerfish are one of my freaky favorites.

[narrator] The Bathyal Zone, also known as the midnight zone,

because no sunlight ever reaches it,

begins 3300 feet beneath the surface of the ocean...

this is the hunting ground of the anglerfish.

They attract prey with a lantern-like light

that dangles from their heads powered by bacteria.

We do know that anglerfish can grow up

to about three feet in size, like what we see in the video.

[narrator] And these creatures are hairy.

The angler fish is covered in hundreds of sensitive

strand like antenna, which allows them to detect the movement

of prey in the pitch black world they inhabit.

If this is a rare example of an anglerfish

washed up on shore,

it's not a good sign for Filipinos.

A pending earthquake could be potentially

responsible for rocking the world

of one of these deep sea creatures

and presenting it on their beaches.

[narrator] The Philippines has over 250 volcanoes

and suffers 600 earthquakes a month.

Most are small, but big ones can be deadly.

It's got to be something extraordinary

to bring a creature from the deep sea up to the shore.

[narrator] In 2018, researchers in the seas

of the Philippines recorded

the deepest underwater volcanic explosion

ever nearly three miles below the surface of the ocean.

Another similar blast could have brought this monster onto dry land.

These creatures spend their entire life

the deepest depths of the ocean,

and when they die, they sink to the bottom.

So, it's incredibly rare and improbable to see one

on the surface or let alone on a beach.

[narrator] An anglerfish would explain the hairs,

but not the mysterious unnaturally black bones.

The fishermen in the video end up burying the beast

because they're overwhelmed by its sickening stench.

Whether it was an angler fish or not,

locals fear what might come next.

Life in the deep sea is strange enough.

So, when one of these creatures

rarely washes up on our beaches,

it is quite a sight to behold.

[people speaking in foreign language]

[narrator] Now, Surrey, a county in the south of England.

August 1st, 2020.

It's early evening.

A group of friends are walking in the hills.

So, this looks just like a normal day in the British countryside.

Nothing seems really out of the ordinary.

[narrator] Suddenly one of the boys

captures something emerging in the distance.

What... What...

[gasps]

Oh.

What the hell is that?

[narrator] Four identical looking hooded figures

moving in an unnerving procession.

They're walking single file

across the camera in front of us

and about 300 yards in the distance,

slowly moving methodically, one behind the other.

Hooded figures, generally not good news.

[narrator] Coming up,

are these followers of a pagan cult

about to make the ultimate sacrifice?

[Karen] There's what's known as the Wicker Man,

a gigantic effigy of a man stuffed

with living people and set alight.

[narrator] In England, a young man films

four white ghostly figures walking in procession up a hill.

Their peculiar clothing reminds historian, Karen Bellinger,

of a blood thirsty cult that held these islands

in the grip of terror 2000 years ago.

What I'm thinking looking at these people

is maybe they're somehow connected to Druidic rites.

[narrator] Druids were the high priests of prehistoric Britain.

When the Romans arrived in 43 A.D.,

they were shocked by the priests' thirst for bloody human sacrifice.

There's one practice that was very well publicized,

and that was the creation of what's known as The Wicker Man.

A gigantic effigy of a man stuffed

with living people and set alight.

Now, these were typically criminals

or other enemies of the Druids.

[Tony] The most important dates

in the Druid calendar was Lammas Day on the 1st of August.

Guess when this video was recorded?

The 1st of August.

[narrator] But according to the Roman historian Tacitus,

the blood-soaked Druidic religion

was stamped out by the legions in a ruthless purge

in the year 61 A.D., almost 2000 years ago.

Anthropologist Dustin Growick looks at the bizarre costumes

and connects the mysterious figures

to a notorious British institution that lies nearby.

Broadmoor is the real life Arkham Asylum, and in Britain

this is where they keep the criminally insane.

[narrator] Broadmoor Criminal Lunatic Asylum

opened in 1863 as a secure hospital

for housing the country's most depraved killers.

Escape is supposed to be impossible.

But in 1952, serial killer John Straffen,

escapes from Broadmoor while on cleaning duties.

Within hours, he kills a five-year old girl.

Straffen is recaptured on the same day.

[Linda] And in 1981, double murderer, Alan Reeve,

escapes the institution by scaling an 18 foot wall

using a grappling rope he made himself.

After he scaled the wall,

Reeve was picked up by his then girlfriend,

Pat Ford, and they managed to evade all the roadblocks

and actually make it all the way to Amsterdam.

But it wasn't long before Reeve killed again,

and he ended up in jail there.

[narrator] In 2014, Broadmoor officials announce

that they will decommission an alarm system

made up of 13 sirens in the local area,

replacing it with social media and news alerts

in the event of an escape.

Locals are shocked.

So, it's possible that if someone had escaped,

people wouldn't know.

Are these four hooded figures somehow related to Broadmoor?

Could they possibly be escaped patients?

[narrator] In 2011.

Broadmoor reveals that it is taking

on a pagan priest in its chaplaincy

as an audit of inmates

had found a number had turned to Britain's

old pre-roman religion, the faith of the Druids.

If these are psychiatric patients,

who have turned their back on society,

it could be very worrying.

[narrator] No escaped patients were reported on the day

the footage was shot and after the figures

disappeared from view, they were not seen again.

Who they were or what they were doing

remains a troubling mystery.

When you see a group of hooded figures like this,

especially draped in white, like they are,

you can't think that this is gonna end well.

This is not a good scene.