All language subtitles for m.f.a.s02e08.1080p.web.h264-cbfm_track3_[eng]

NARRATOR: A massive crater
materialises in the Arctic tundra.

- Why is there a colossal gaping
hole right there? It makes no sense.

NARRATOR: The sweltering desert
reveals a forbidden chasm.

- If you go in,
you're never coming out.

NARRATOR: Dark openings infect
the edge of a vast frozen landscape.

- That's so... weird.

NARRATOR: And satellite images
expose a mystifying, icy void.

- What is it and why is it there?

NARRATOR:
Everywhere we look on our planet,

there's evidence of the past.

In nature...

in buildings...

in relics.

Each holds a mystery that technology
now allows us to see from above.

What new secrets are revealed?

- (sonar bleeps)

NARRATOR: The surface of our planet
is full of strange terrains.

Some are in plain sight,
but with unexplained holes

that delve deep into the earth,

the view from above
could provide a key

to solve the mysteries
that lie below.

The immense tundra of Yamal,
a remote peninsula

in the Siberian Arctic, contains
a deeply mysterious discovery.

- Whoa, what is that?

NARRATOR:
A huge and inexplicable crater

has emerged in the permafrost.

- Why is there a colossal gaping
hole right there? It makes no sense.

- Is that a hole? It's massive!

NARRATOR:
This gigantic chasm in the Earth

is about 20 metres wide.

- Ho...ly...

- If I were to draw a comparison,
I'd say it kinda resembles

an entryway, a portal into an abyss.

NARRATOR: Its appearance in 2014
has puzzled scientists

around the world.

What could have created
this mysterious hole

in the Siberian tundra?

GEORGE: It looks like something
heavy hurtled through the sky

and pounded into the Earth.

Could a meteorite have caused this?

NARRATOR: Every year,
millions of rocky shards tumble

through outer space and penetrate
the Earth's atmosphere.

CYLITA: Most look
like shooting stars

and vaporise before reaching
the Earth's surface.

But thousands survive, and they
collide violently into the ground.

GEORGE: If you look at images
of impact craters -

even just the ones in Russia -

they look a lot
like what we have here.

NARRATOR: Almost 2,500km away,
near the Russian city of Yakutsk,

could the Macha craters
give us a clue?

- It's believed that
about 7,000 years ago,

a small asteroid broke up in the sky

and five meteorites crashed
into the Earth.

The biggest crater is 300m wide -

just imagine the explosion needed
to create something that huge.

- But nothing compares to the epic
Siberian Tunguska Event.

It happened in 1908, but it's still
the largest impact event

in recorded history.

NARRATOR: South west of Yakutsk,

the Tunguska meteorite disintegrated
above the ground

in a deafening blast.

SHEILA: Experts say it was 60m wide,
and the fireball it created exploded

with a thousand times more power
than the Hiroshima bomb.

TORRI: An estimated 80 million trees
over an area of 2,000 square km

were flattened -
that's the size of Tokyo.

Over 100 years later, many of
the trees have still not grown back.

CYLITA: An impact creator isn't
a bad guess.

This hole is about 20m wide
and over 50m deep.

Could something that huge go
completely undetected by satellites?

- A meteorite that size,
you would have heard about it.

It would have been
the breaking news everywhere.

- So, what is this blasted thing?

- I can tell you what it looks like.

A sinkhole -
likely caused by melting ice

wreaking havoc in the permafrost.

- Permafrost is made out of soil.

It has water in it,
but the water is frozen,

and the organic material in the soil

is often low growing mosses,

the sort of things
you'd see in a bog.

So, you can think of it
as frozen peat.

CYLITA: We know climate change
is causing the permafrost to melt,

so it makes sense that the ground
underneath is going to be weakened.

TORRI: Permafrost, that's expected
to be frozen all-year round,

is thawing and collapsing
around 200% faster

than expected in the last 20 years.

DAN: What does this mean
for the Arctic landscape?

Is it giving us a final warning
before all hell breaks loose?

This thawing is creating a type
of terrain called thermokarst -

this irregular surface
of holes and hollows

as the icy permafrost liquefies.

NARRATOR: In countries like Sweden,
thermokarst melted the landscape

so severely,
it created hundreds of lakes.

CYLITA: And thermokarst gullies
are appearing in places like

the Taymyr Peninsula in Russia.

- What happens in thermokarst
is when water freezes,

it expands,
and when it melts, it contracts,

so this differential freezing
and thawing

creates an uneven topography.

NARRATOR: And some things
under that topography

haven't changed in millennia.

- Besides the landscape shifting,
another potentially scary thing is

when permafrost thaws,
it releases ancient bacteria

and viruses that have been frozen
in the ice.

- Scientists have discovered
microbes more than 400,000 years old

in thawed permafrost.

- Now, I'm quite certain
that not very many people are

all that enthusiastic about letting
ancient viruses on the loose.

- So, are we dealing with an extreme
example of thermokarst in Siberia?

CYLITA: Although what we're seeing
in Siberia is very strange,

the hole itself looks quite
different than thermokarst sinkholes

which are irregular
in their appearance.

This Siberian hole
is almost too perfect.

NARRATOR: Considering this hole in
Siberia is so defined and circular,

is it possible that it's not
a natural occurrence?

- Could it be man-made?

Just over 2,000 km away,
in Mirny, Siberia,

is the Mir Diamond Mine.

It's more than 500m deep
and has a diameter of 1,200 m.

- It's one of the largest man-made
cavities on the entire planet.

Is it possible
that mining is the reason

for this mammoth hole in Siberia?

GUY: A huge amount of mining happens
in the Arctic. It's got lots there.

I mean, besides diamonds, it
holds vast quantities of minerals.

You've got things like phosphate,
bauxite, iron ore, copper,

nickel, you name it,
it's in the Arctic.

DAN: But mining requires a ton
of equipment and power.

I don't see any signs of that
around this hole,

so mining doesn't make sense
in this case.

NARRATOR: So, what is it?

To solve the mystery
of the mammoth hole,

another clue might be found
from above... in the numbers.

GEORGE: Reports from Russia claim
that since 2014,

over 20 of these openings
in Siberia have materialised

in the Yamal and Gydan Peninsula.

- What the heck could have created
so many terrifying black voids

in the permafrost?

- What about a covert military
operation? It's not impossible.

During the Second World War,
Hitler secretly tunnelled deep

into the ground to build a huge
supergun under a hill in France.

NARRATOR: If it wasn't discovered
by the allies and destroyed

in a bombing raid, the supergun
could have radically changed

the outcome of the war.

TORRI: And during the Soviet era,

Siberia was home
to many Cold War installations.

Who's to say that Russia
hasn't recently started building

secret missile silos?

- If you think about it,
strategically, the far north offers

the shortest route to America for
intercontinental ballistic missiles.

- The region also represents
the first line of defence

against a NATO attack.

DAN: Or maybe they're related
to Russian space research?

Could they be launching
rockets on the sly?

- But if any of this were true,
wouldn't we be seeing some concrete

and metal in these cavities? I mean,

I don't think it's possible
for a launch pad to be built from,

what is essentially, dirt.

GUY: If these things are, in fact,
launch pads, I'm gonna be

seriously impressed with the state
of Russian engineering!

- Anything human-made means
digging down into the Earth.

And if we move closer to the edge
of the cavity.

we get a better look at the
permafrost scattered all around it,

something just doesn't add up.

- Can the debris somehow explain
how these holes emerged?

NARRATOR: In the view from above,

the pattern
of the discarded permafrost

makes something very clear.

This chasm was not created
from a collapse of the Earth

or by excavation.

- Although no one has seen
these pits appear,

people have heard a deafening blast
from quite a distance away.

- Oh, that does not sound good.

- These holes were created by
a massive explosion from below!

- Around many of them, there's
a very clear blanket of ejecta.

There's stuff that's been
thrown out in the hole.

NARRATOR: What could be bursting out
of the permafrost powerful enough

to create a pit that's 20m wide?

- An exhaust pipe from hell
sounds about right.

- What else could explode
from the ground out?

GEORGE: When I think of Siberia,
volcanoes aren't the first thing

that pop to mind,
but it is worth considering.

- Well, now that's not a bad idea,
but are there volcanoes in Russia?

GEORGE: Russia's Kamchatka Peninsula

is one of the world's most
concentrated areas

of geothermal activity,
with about 30 active volcanoes.

CYLITA: The Kamchatka Peninsula
extends into the Pacific Ocean

along the infamous Ring of Fire.

NARRATOR:
But since the Kamchatka Peninsula

is 4,000km away from Yamal,

is it reasonable to think
these holes are active volcanoes?

GUY: Although the craters
resemble a volcano,

complete with a raised edge
and ejected substances,

Siberia's not a volcanic landscape.
There's no boiling lava.

There are no giant vents
of blistering hot fire.

- And according to witnesses, the
holes begin to fill up with water

not long after they were discovered.

They turn into what looks like
small lakes in the landscape.

NARRATOR: So, what is the cause of
these enormous, exploding craters?

- Could these holes be the aftermath
of some kind of mud volcano?

Like a lava volcano,
a mud volcano can be the result

of tectonic pressures creating
a geological pathway

where materials below the ground
can be pushed up.

- But is Siberia a place where
geophysical forces are at work?

GEORGE: Mud volcanoes are often
associated with hydrocarbon gases,

and this part of Siberia is home to
Russia's vast oil and gas reserves.

- Could gas be the reason
for these enormous expulsions?

CYLITA: No evidence connects
nearby oil

and gas infrastructure or pipelines

to these holes, so scientists don't
know exactly what is happening.

- I want to know,
has anyone actually investigated

one of these holes?

CYLITA: In 2015,
Scientists from Moscow's

Skolkovo Institute
of Science and Technology

travelled to Siberia
to take a closer look.

GEORGE:
They took samples of air and water

from boreholes around the crater.

What they discovered was
a very unexpected clue -

unusually high levels
of one single gas.

Methane.

- Are these holes in Siberia
methane explosions?

I wouldn't wanna be near one,

but it sure would be
something to see.

NARRATOR: Could the key
to this mystery be methane?

- It's considered
a super greenhouse gas,

because it's 25 times
more powerful than carbon dioxide

and contributes
to the warming of the planet.

TIM: There's a lot of methane
in the permafrost in Arctic regions,

and that leads to a little bit
of a scary situation.

GEORGE: Estimates say there is
over one trillion tons of methane

stored beneath the Arctic.

It represents what some climate
scientists have termed

a methane time bomb.

- The first hole appeared in 2014
after one of the hottest years

on record in Siberia, and all
of them since have also appeared

during uncharacteristically
warm temperatures.

SHEILA: So, is climate change
somehow responsible for these holes?

TIM: If we warm the planet,
the permafrost will melt,

that's going to release methane
to the atmosphere,

which will enhance
the greenhouse effect,

which will cause
more permafrost to melt.

- So, we could enter
this feedback loop

that increases global warming
very rapidly.

NARRATOR: But what does the melting
of the permafrost surface

have to do
with these deep holes?

- The current hypothesis is that
warming temperatures in the Arctic

haven't just caused the ground
to thaw at the surface,

but also within these thaw chimneys
known as 'taliks'.

TIM: The Earth has
this normal geothermal gradient

that the deeper you go,
the warmer it gets.

GEORGE: If the permafrost thaws
in certain places,

the extra weight may force methane,

that's been under the Earth
for millions of years,

up through this talik.

- So, essentially these taliks
are creating a route

for ancient and intensely
pressurised methane.

- It's like squeezing the bubbles
on bubble wrap

GEORGE: Like a large pimple,
the Earth bulges on the landscape

as pressure underneath grows.

Eventually, with enough pressure,
the gases erupt,

tearing a cavity
in the earth's surface.

NARRATOR:
But that's just the latest theory.

- No one is certain
simply because nothing like this

is happening
anywhere else on the Earth.

These craters have shocked
the entire scientific community.

NARRATOR: Researchers are now using
satellite data to locate the methane

swellings before they explode.

- Documenting these explosions isn't
gonna stop them from happening,

but it could help us get a better
understanding of what they are.

Because one thing is for sure -
any large-scale increase

in methane emissions
have scientists seriously concerned.

CYLITA: What's happening will not
just have consequences for Siberia

and the Arctic, it will ultimately
affect all life on this planet.

NARRATOR: From exploding
chimneys of permafrost

to a crater in the sweltering sands,

some of the Earth's
most mysterious holes

will only reveal their secrets
through the view from above.

Far from the Arctic circle, hidden
deep within the scorching desert

in Al Mahara, Yemen,

a dark void exists
in the ancient Barhout valley.

- Whoa. Ah...
that is very, very, eerie.

- There appears to be a black hole
in the middle of the desert.

GEORGE:
There are striations or ridges

that almost looks like a throat,
as if the desert is screaming.

- It looks like a gateway
to another dimension.

I mean, look at that thing!

NARRATOR: The view from above
reveals a 30m chasm

that resembles
the stuff of nightmares.

Its official name is
the well of Barhout...

..but it's also known as
the well of hell.

- If you go in,
you're never coming out.

NARRATOR: So, here's the question:
Is this hole natural

or supernatural?

Frightening stories of the well
have been woven deeply

into the culture for centuries.

CYLITA: Legends say it's an ancient
prison for genies and dark spirits.

Many consider it bad luck
to even speak about the well.

- I can almost imagine
some horrible,

guttural sounds coming out of there.

- Some visitors to the well
have actually claimed

that they hear strange voices
and screams,

and some even complain
that there's this

kind of foul odour emanating
from the kind of

poisonous water in the bottom
of this really shadowy pit.

- OK, but if we calm down
for a second,

is it possible
that this Well of Hell

is actually just an ancient well?

- Generations ago,
the well-diggers of Yemen

would have used hand shovels
in their search for water.

- Unlike modern wells
that are dug by machines,

could the Well of Hell be
one of the oldest and deepest

hand-dug wells in the world?

NARRATOR: Almost 6,000km
from Yemen, in Brighton, UK,

You'll find what's known as
the world's deepest hand-dug well.

- The Woodingdean Water Well
was originally dug to provide water

for a workhouse -
a place of work and shelter

for Victorian England's poor.

NARRATOR: The dig started in 1858
and took four years

to finish with the well
being only one metre wide.

KAREN: Workers had to scale
the shaft in complete darkness

on rickety ladders.

And it was so hot inside
that many of the men worked naked.

- That's scary on so many levels.

GUY: At 390m deep,
the Woodingdean water well

is deeper than
the Empire State Building is tall.

- And quite astonishingly, only one
person plunged to his death

during its construction.

- I'd like to know how many souls
have met their fate

in the Well of Hell,
and how many people

would have been needed to dig it?

NARRATOR: The well of hell is 30m
wide and 112m deep -

a space large enough to accommodate
over one million people.

A hole that large would have been
a nearly impossible job

for Bedouin well-diggers hundreds
or maybe thousands of years ago.

GEORGE: Are we sure
this is an ancient water well?

If the locals claim the water below
is foul smelling and poisonous,

maybe this was not meant to be
a well for drinking.

NARRATOR: If it's not a water well,
what else could this hole be?

Perhaps the answer could be found
within the texture

of the walls themselves?

- The walls are really strange.
They don't look hand-carved.

Instead,
they look almost corkscrewed.

GUY: Military enlistees that were
deployed to camps in parts

of the Arabian Desert claimed that
they occasionally came across

this kind of tar-like black matter
containing sulphur.

Now, what could that be?

GEORGE: Hydrogen sulphide is
a flammable, colourless gas

with the very familiar smell
of rotten eggs.

Could this hole be an abandoned
entrance to a not-so-old well

that was dug with a drilling rig?

CYLITA: It's known that the Iraq
Petroleum Company once conducted

exploration in northeast Yemen.

KAREN: But oil drilling has only
happened in the Middle East

within the last 100 years.

Surely the Well of Hell
is older than that.

- The only way to solve the mystery
of what this ominous hole

in the desert is,
is to rappel down into it.

NARRATOR: Safely climbing down
into an enormous cavern

is not an easy task,
but the Omani cave exploration team

wants to find out
what the well of hell really is.

- We really wanted to know
what existed below

this large opening
in the middle of the desert plain.

- Knowing the legend that claims the
hole was filled with dark spirits,

the locals are probably concerned.

DAN: Entering
a genie-infested hellmouth...

what could possibly go wrong?

KAREN: A king's ransom couldn't
tempt me to go down in there.

It's terrifying.

- Loads of stories have been
invented around this cave.

They probably wanted to create
kind of a danger zone,

to prevent their children or
any other person to get close to it.

NARRATOR: The team is hoping to
discover what the well of hell is,

and dispel any myths of evil
creatures lurking at the bottom.

- One of the most famous legends
claims that the Well of Hell is

a prison for genies,
also known as 'Jinn'.

In Arabian and Muslim mythology,
'Jinn' are intelligent

but rebellious spirits
intent on possessing humans.

- And apparently,
Jinn cannot be seen by humans,

so... good luck with that.

MOHAMMED: The entrance of the cave
is almost perfectly circular

and then it goes
into kind of widening geometry

as it goes down into
a big, kind of, uh, pot.

CYLITA: With the sounds
of falling water coming from below

and these small patches
of vegetation hugging the walls,

it seems like the well contains
its own tiny ecosystem.

MOHAMMED: There are at least
four waterfalls actually within,

and it makes the environment
just amazing and spectacular.

NARRATOR: Everything inside
indicates the passage of time,

with stalagmites
reaching over 9m tall,

and stunning multi-coloured
cave pearls

formed over thousands of years
by the dripping water.

CYLITA: The ecology inside the well
is so interesting,

and just breathtaking to look at!

- It's quite amazing down there.

NARRATOR: Perhaps a hole over
6,000km away with a similar interior

could shed some light on
what this hole is?

GEORGE: The Well of Barhout reminds
me of an enormous cave system

in Vietnam, Hang Son Doong.

It's extremely large -
a 747 could fly right through it.

NARRATOR: The Hang Son Doong cave's
enormous stalagmites developed

over millions of years,
and the river flowing through it

is likely responsible
for its formation.

GEORGE: And it has
a giant opening at the top,

so access to sunlight
means vegetation can grow inside.

NARRATOR: Is it possible the well
of Barhout is a much smaller version

of the Hang Son Doong?

CYLITA:
Looking at the interior shape,

it doesn't look like
a cave, exactly.

Could it be a sinkhole?

KAREN: It looks a lot like
a sinkhole in Nevada

called the Devil's Throat.

It appeared in the early 1900's

and has collapsed further
over the years.

It's now about 30m wide
and 40m deep.

NARRATOR: And southeast
of the Devil's Throat,

there's another sinkhole

with an equally ominous appearance
from above.

GEORGE: The Black Hole Of Chile -
a sinkhole that appeared

in July 2022 near the small town
of Tierra Amarilla.

It collapsed to more than 50m
wide and over 200m deep.

That's large enough to swallow
France's Arc De Triomphe!

- So, what is this place?

GUY: After gathering
photographic evidence,

collecting samples of rocks
and water and vegetation,

what scientists concluded
is that the Well of Hell

is in fact a sinkhole that developed
millions of years ago.

NARRATOR: Although it's a desert,
the view from above reveals

a landscape covered
by layers of limestone beds,

which are very porous.

MOHAMMED: And when they mix
with waters, they tend to dissolve.

With time, you get vertical cavities
as well as horizontal cavities

connecting together and
eventually they formed chambers.

NARRATOR: Some of these underground
aquifers and chambers collapse,

creating the many caves
and sinkholes that can be found

in south Yemen, nothing quite
as large as the well of Barhout.

KAREN: And it's incredible to think
that this sinkhole

has existed in Yemen for so long

and not a single human
has been inside of it.

NARRATOR: At least not any human
in modern times.

- If they had, we'd see their bones

because there would be
no getting out.

MOHAMMED: People were saying
that this is probably

a water well dug by Jinns.

Obviously, that's not true.

It's just a beautiful structure that
have formed over thousands of years.

NARRATOR: So, the mystery of
the well of Barhout has been solved,

and now that we understand
this sinkhole's unique interior,

it's become a new geological
wonder in Yemeni history.

- So, maybe not a well from hell,

but definitely a sinkhole
I don't care to visit.

NARRATOR:
From ancient desert folklore

to modern secrets in the ice,

the view from above can help
decipher strange openings

and their mysteries
in the depths below.

Over the western edge
of Greenland's ice sheet,

a dark outbreak invades
the immense expanse of white.

- Oh, that's so... weird.

NARRATOR: Thousands
of irregular-sized black holes

pockmark the frozen surface.

- All those spots look creepy,
like some kind of disease.

- I've never seen anything
like that before.

- This kind of change
in the ice can't be good.

NARRATOR:
Greenland's ice sheet contains

almost three million
cubic kilometres of ice.

- So, the question is
why is this part of the ice sheet

riddled with so many holes?

- And what the heck are they?

CYLITA: Whatever they are,
it's made an enormous impact

on the Greenland landscape.

- The sheer number of vertical
shafts is extraordinary.

- What could be the cause of them?

NARRATOR: If we take a larger view
of Greenland from above,

we see how much access
it has to ice and to water.

- What about fishing holes?

- That seems unlikely.
That's just a lot of ice holes.

NARRATOR: Is it possible
any kind of ice fishing would create

this many holes?

- Maybe this strange landscape is
the former site

of an ice fishing competition?

NARRATOR: Could be.

Over 3,000km away, in Minnesota,

The Brainerd Jaycees
Ice Fishing Extravaganza

has taken place for over 20 years.

- It boasts being the largest
ice-fishing contest on Earth.

Tens of thousands of fishers
create over 30,000 holes.

GEORGE: The number of holes
sounds about right,

but it's not cheap
to get to Greenland.

Would thousands of fishers travel
there for a tournament?

- And ice fishing holes
are normally about 10 inches wide.

Big enough to haul out
a monster catch,

but not so big
that you could fall in.

NARRATOR: If we take a closer look
at the view from above,

there may be another clue.

GUY: Some of the shafts
are quite wide,

they're like a kinda metre across,

but others are really very small,
you know, so small

it looks like someone just got a hot
poker and stabbed it into the ice.

TORRI: They're a lot smaller
than I thought.

GEORGE: If we look at the edges
of the openings,

there's no evidence of chopping
or drilling into the ice.

- If these holes weren't made
for fishing, what are they?

NARRATOR: It may be easier to
uncover what these holes are

if we investigate other nearby
phenomena in the ice from above.

CYLITA: Greenland is full
of what are called melt water lakes.

- Those lakes can lead
to the natural creation

of vertical ice caves
called moulins -

a type of sinkhole formed when
a melt stream on the surface

of ice develops a weakness.

DAN: The streams become rivers,

and that leads to huge holes
that sink deep into the ice.

NARRATOR: Moulins can be
10m wide and, astonishingly,

hundreds of metres deep.

They form on glaciers
and ice sheets all over the world.

GEORGE: By draining the melted water
back into the sea,

they basically act as
a natural plumbing system.

TORRI: Could these holes
in the Greenland ice sheet

be miniature moulins?

KAREN:
Moulins are a sight to behold,

but they don't look like
the circular black shafts

in the Greenland ice sheet.

CYLITA: There's no flowing water,
and although they vary in width,

they're not typically known to be
more than five metres deep.

NARRATOR: Perhaps the answer
lies within the bottom of the holes?

What is it that makes them so black?

DAN: Researchers investigated
the Greenland holes,

and in the still water at the bottom

they found something
totally unexpected -

this black, gritty sludge.

NARRATOR: Why and how could
black sludge get into the bottom

of ice shafts
in the Greenland ice sheet?

Is there some kind of
foreign invader?

- It's a mystery wrapped up
inside an enigma

inside an icy black hole.

- Glacier microbiologists were able
to identify it as cryoconite

and the mysterious openings
in the Greenland ice sheet

are called cryoconite holes.

- If someone says to me
a moniker, like, cryoconite holes,

I'm thinking we're talking
about a kind of Martian

or extraterrestrial landscape.

What exactly are they?

- Over 150 years ago,
Arctic explorer Nils Nordenskiold

discovered a black windblown dust

collecting on the ice
during his visit to Greenland.

NARRATOR: Nils gave the sediment
a fancy name - cryoconite.

In Latin, 'cryo' means ice
and 'conite' means dust'.

- It is believed that cryoconite
is carried to the ice by wind,

but how can dust collect right
here and nowhere else?

NARRATOR: The location
to the coast is likely the key,

and the direction
of global air patterns.

Cryoconite can also be found
in other Arctic

and Antarctic coastal areas.

In Greenland, it inhabits an area
called the 'dark zone'.

- This, to me, is starting to sound
a bit like a horror movie.

What on Earth is a dark zone?

CYLITA: A dark zone is exactly
what it sounds like.

It's the darker areas
on the ice sheet.

Over the years, the cryoconite
increases and so does the dark zone.

TORRI: But what exactly does
cryoconite and dark zones

have to do with these deep holes
in the ice?

KAREN: If cryoconite is a black,
airborne pollutant,

where would it have come from to end
up in Greenland's ice sheet?

NARRATOR: Perhaps the answer
can be found 140 years in the past

and over 12,000km away,

when a massive eruption
poisoned the skies.

GUY: Volcanoes are a possibility.

I mean, look back to 1883
when you have particulates

from the Krakatau volcanic
eruption in Indonesia.

They were seen 13 days later
on the other side of the world.

Krakatau created red sunset glows

as far away as New York
for the next three years.

NARRATOR: For Greenland, the source
of the pollutant

could lie around 1,200km away.

CYLITA: The closest volcanic
landscape from Greenland

is in Iceland who've had their fair
share of eruptions over the years.

KAREN: In 1783,
volcano Laki erupted for over a year

and caused an immense ash cloud.

GUY: So much of the agriculture
and livestock in Iceland

and all across Europe were poisoned

from the volcanic ash
that rained down for months.

NARRATOR: And more recently,
another Icelandic volcano

had a more debilitating effect
on the skies.

TORRI: In 2014, many flights in
and out of Europe were cancelled

because of the enormous eruption
and subsequent black ash clouds

from Iceland's volcano Bardarbunga.

GEORGE: But forest fires, factories
and ejected fuel are

probably closer in proximity
than the volcanoes of Iceland.

Is it possible that soot has created
the Cryoconite holes

in the Greenland ice sheet?

CYLITA:
With a population under 60,000,

and a huge fishing industry
in comparison,

the biggest polluter in Greenland
isn't from cars.

NARRATOR: Scientists believe
the leading cause of pollution

in Greenland's cryoconite holes

comes from black
carbon emitted by ships.

- For Greenland, it's an important
but very sobering discovery.

NARRATOR: But it's not just
pollution that's been found inside

the cryoconite holes in Greenland.

They also discovered something
that was completely unexpected...

life.

- What kind of living organism
can actually exist in

thousands of these holes right at
the edge of the Greenland ice sheet?

NARRATOR: After careful studies,
scientists were able to identify

a bloom of glacial algae
called zygnematophycea.

- OK, but how in the world
did they get there?

NARRATOR: It turns out, dust,
water and carbon from ships

are the perfect ingredients
to spawn algae.

DAN: The researchers also
found Cyanobacteria

and tardigrades
in the cryoconite holes.

Tardigrades are also
called 'water bears'.

They're super cute,
and they're also survivors.

They can live at the bottom
of the ocean,

on top of mountains,

they can even survive
in the vacuum of space.

And if you take
all of the Earth's ice,

it's estimated that there are

a hundred million billion
trillion micro-organisms

living in the top two metres of it.

- What I want to know is,
how far down into the ice

can these microorganisms live?

NARRATOR: In 2018,
a group of international scientists

explored some moulins
north of Greenland's dark zone.

They wanted to go deeper than
anyone else had ever travelled

inside a glacier.

- Because of the flowing water and
potential structural insecurities,

instead of going down there
themselves, they sent down a drone

with a bright spotlight, and were
able to investigate the entire area.

- I'm afraid to ask,
but what did they find down there?

DAN: At the bottom,
they found an immense ecosystem

of microorganisms living
hundreds of metres beneath the ice.

NARRATOR: Cousins
to Greenland's microorganisms,

they're known as extremophiles
because they can survive and thrive

in the most inhospitable regions
of the Earth.

- We're talking the coldest
and darkest places on glaciers

to deep underwater thermal vents

to searing hot lava from volcanoes.

- The discovery of these life forms
is truly a scientific marvel.

DAN: But as impressive as they are,

the problem
with all those microorganisms

living in the Greenland ice

is that they are at least partly
responsible for melting it.

GEORGE: When dark sediment
builds up on the ice,

it decreases the 'albedo'
or reflectivity of the ice,

and increases the absorption
of heat from the sun

which causes the ice to melt.

As the ice melts,
the black matter, or cryoconite,

sinks down into the surface.

NARRATOR: It's this process that
causes the holes in the ice sheet.

These dark microorganisms
can melt the ice surface

by more than 10cm
in just a few hours.

DAN: Using satellites and drones,

scientists are collecting data
from this microbes to discover

their impact on the ice
and the global climate.

GEORGE: These newly discovered life
forms in Greenland and elsewhere

will, without a doubt,
continue to survive and thrive.

- We can only hope that the rest
of the natural world will as well.

NARRATOR: Whether you're searching
in holes with microscopic secrets

or gazing at satellite forms,
the view from above can uncover

the truth
in the shadowy spaces below.

Like in the ice-packed frozen
deserts of Antarctica.

- This place feels like
it's frozen in time.

NARRATOR: In 2017...

An enormous, dark shape appeared
where there was once... nothing.

- Well, that's unexpected
in a place like Antarctica.

TORRI: I can't really tell
what it is,

but it doesn't look like it
belongs with anything else there.

NARRATOR: This inexplicable void was
discovered by a spectroradiometer,

NASA's terra satellite, while
studying the Antarctic from above.

- Nothing, nothing, nothing,
and then, all of a sudden, wham.

This strange-shaped... shape.

- So, the question is:
what is it and why is it there?

GEORGE: My first thought,

it might be something
we're already familiar with...

algae.

NARRATOR: Could algae
from over 15,000km away

in Greenland's dark zone give us
a hint at what we're looking at?

CYLITA: Greenland's dark zones
consist of algae,

bacteria, and black carbon soot
from passing ships.

Could this shape in Antarctica be
from a similar combination?

DAN: Antarctica's algae blooms
come in a rainbow of colours,

but they don't all come
from pollution.

In fact, scientists say a lot of
Antarctica's algae feed off

the nitrates found in seal poop
and penguin poop.

GEORGE: Knowing this,
is it possible that the excrement

of Antarctic wildlife created
a dark bloom of microalgae?

- You know, I feel like
that area is much too large

for a faeces-fuelled algae bloom.

NARRATOR: Researchers estimate
this unknown form to be

about 9,500 square-kilometres,
larger than Puerto Rico.

TORRI: So, what is this enormous,
mystifying shape?

To me, it looks like a lake of some
sort, but it's a very dark lake.

- Could it be a lake full
of decomposing slime or tar?

- It happens. The Black Sea has
a depth of over 150m

and is the world's largest
body of water

that contains hydrogen sulphide.

TIM: The Black Sea has
very poor circulation.

It's only connected
to the rest of the world's oceans

by a little tiny strait
by the Bosphorus.

So, the water doesn't circulate
with the rest of the oceans.

NARRATOR: This means the salty
sea water in the deep layers

and the fresh river water
on top don't mix.

CYLITA: So, without water flow,
living things can't thrive, right?

Dead organic materials will sink to
the bottom layer

and they'll produce hydrogen
sulphide as they're broken down,

eventually becoming covered
with this kind of black sludge.

NARRATOR: Could that be
what's happening in Antarctica?

Is this a dark lake being impacted

by high levels of hydrogen sulphide?

TIM: The waters in Antarctica tend
to be more oxygenated,

less likely to accumulate
these black organic sediments

that would produce
hydrogen sulphide.

- There's plenty of pristine
freshwater there.

It's estimated 70% of the world's
freshwater reserves

are all locked up
in Antarctica's ice.

NARRATOR:
So, if it's not hydrogen sulphide,

what could be making it so black?

- Could it just be black ice? It can
make a lake look incredibly dark.

DAN: Black ice isn't
just something you drive across

when you're wiping out in your car.

It's also found in bodies of water.

GEORGE: Known as congelation ice,
it has no oxygen,

which means there are no bubbles
to give it a white appearance.

TIM: Perfectly clear ice
may look black because

the light passes right through it,
it's not bounced back to our eyes.

DAN: So, could it be
that we're looking at a lake

with thousand-year-old, highly
compressed, airless, black ice?

Cool.

CYLITA: Black ice has
this very glossy surface.

And it's hard to tell,
but in this image from NASA,

the lake doesn't really appear
to have that quality.

NARRATOR: Perhaps another view
from above can give us a clue.

A few weeks after the first image
was taken,

NASA's spectroradiometer registered
a different unexplained shape

at the same exact spot.

- Well, now,
that defies explanation.

- How is this possible? A body
of water can't just morph like that.

NARRATOR: And not long after,

another image makes
something else very evident.

The black shape is getting larger.

- Very strange things
are happening in Antarctica.

- So, now we have two mysteries:

what is this thing,
and why is it ballooning out?

- Considering its growth, maybe
what we thought was a lake of water

is actually a lake of oil.

CYLITA: On the opposite end
of the planet, countries are racing

to gain access to oil reserves.

The Arctic Circle contains
about 13%

of all the unexploited oil
in the world.

NARRATOR: But the production of oil
has always been prickly.

- The infamous Exxon Valdez
spill in 1989

lost nearly 37,000 tons of crude oil

in Alaska's southern coast,
killing over 30,000 birds.

TORRI: More recently in 2020,
satellite images reported

an oil leak
in Russia's Arctic Circle.

Melting permafrost caused a fuel
tank holding 21,000 tons

of diesel oil to collapse, leading
to 135 square mile oil spill.

In the satellite image, there are
no signs of oil production, so...

could we assume that the black shape
is oil seeping up from underground?

CYLITA: Unlike the Arctic where
there is a lot of oil drilling,

Antarctica has
no known oil reserves.

GEORGE: In fact, scientists believe

that if there's any oil
in Antarctica, it lies offshore.

But so far,
none of it has been exploited.

- This large shape has me
totally baffled. What is it?

NARRATOR: If we zoom in
closer on the view from above,

new evidence appears inside.

- What is that? Is that a ridge?

- Oh, it's a hole. Right, cos
this is an episode about holes.

SHELIA: What's a hole doing
in Antarctica?

One that's increasing in size?

- What about a sinkhole?
Are there sinkholes in Antarctica?

- They're not common,
but they happen.

In 2019, at the top of
East Antarctica's Amery Ice Shelf,

a massive 750 million cubic
metre lake vanished.

750 million cubic metres -

that's so big I've got nothing
to compare it to!

- Technically,
it's called a hydrofracture.

This crack opens up and the lake
just drains like a bathtub.

NARRATOR: Within just three days,
it left an 80-metre-deep depression

spanning 11 square kilometres.

Could this be what's causing
the mysterious hole?

- Is it possible the weight
of the water

shattered the ice shelf beneath it,

allowing it to drain away
in a Niagara Falls-style rush?

- It's possible.
A year before the hole appeared,

researchers discovered
something incredible...

a series of ancient lakes that are
thousands of feet beneath the ice.

- The team believes
that around 15 million years ago,

water got trapped
beneath the ice sheet

in what they dubbed a 'ghost lake'.

These lakes have
never seen sunlight.

GEORGE: The largest of the ancient
lakes had been named Lake Vostok.

It's just under 500 square
kilometres - the size of Cyprus -

and a thousand metres deep.

NARRATOR: Lake Vostok is so large,
you can see its outline from space,

but for at least 15 million years,

it's been covered
by more than 3.5km of ice.

- Wow. So, could the hole be
some kind of exit point

into one of these ancient
ghost lakes?

NARRATOR: That could make sense,
except for one very important clue:

the hole is off the coast
of Antarctica,

which means it's a hole in sea ice.

GEORGE: In the winter, a thick layer
of frozen sea water covers it,

and usually stays frozen
until summer.

TORRI: So, why did this hole appear
in the Antarctic sea ice

in the wintertime?

NARRATOR: When researchers
investigated the history of it,

they found that it's not
the only time a hole has appeared.

GEORGE: Just after the first
satellites were launched,

similar holes were spotted in 1974,

1975 and 1976 -

before they broke up during
the austral summer -

when the ice merged with the ocean.

The phenomenon
is known as a polynya,

a Russian word that roughly means
"hole in the ice".

TIM: Polynyas happen up against
the shoreline quite frequently,

but to have an opening
in the sea ice that far offshore

and to have one that big
was very unusual.

GEORGE: So, the big question
for scientists was:

why would there be a huge hole in
the Antarctic sea ice in the winter?

Why doesn't that spot freeze?

NARRATOR:
That spot is prone to thawing

because about 1,700 m
below the surface

is a submerged mountain-like
feature known as Maud Rise.

When ocean currents interact
with it, deeper and warmer water

is pushed up to the surface,
causing the sea ice to melt.

- And looking back at the time
frames of the holes

from almost 50 years ago,

they corresponded
with extreme cyclone winds.

NARRATOR: Before the 2017 polynya,

we know gusts
of warm and cold air collided,

causing cyclonic winds
and waves in the Weddell sea.

- The best hypothesis is that
somehow warm, moist air

from higher latitudes
makes it into the Antarctic,

which is not common.

TIM: So, if you get a cyclonic storm
over the sea ice,

that may push the ice outwards,

you know, a little bit like tossing
pizza dough and it spreads.

NARRATOR: The combination of cyclone
winds and warm ocean currents

forced upwards create the polynyas.

CYLITA: The ice pack was pushed
in every direction,

away from the centre
of the storm,

dragging floating sea ice
in opposite paths

around the cyclone's centre
creating this opening.

DAN: Warmer climates mean
more cyclones,

and more cyclones mean
more polynyas.

This is what climate change
looks like from above.

- You know, I've gotten over saying
disturbing things about climate.

I used to moderate my language
about it, but we're past that.

Scientists need to tell
everybody how bad it really is.

NARRATOR: Because if humans continue
to ignore the catastrophic changes

in Earth's climate,
we're all on borrowed time.

From exploding permafrost,
to a mythical sinkhole,

to a rash of pollution,
and a huge breach in the ice,

the view from above gives us
a unique perspective

on some of Earth's mysteries
hiding just below the surface.

Subtitles by Sky Access Services