[narrator] They're watching you.
More than 6,000 satellites circle the earth.
Every day, they uncover new mysterious phenomena
that defy explanation.
Arizona's mystery space colony.
These structures witnessed one of the most bizarre
and incredible experiments in human history.
[narrator] The multi-million dollar underwater treasure trove.
[woman] It really is incredible to see
just how far people will go
if there's a chance of getting rich.
[narrator] And Churchill's secret bioweapons lab.
It was so bad
that it earned the nickname the Island of Death.
[narrator] Baffling phenomena, mysteries from space,
what on earth are they?
[robotic sounds]
[distorted signals]
[buzzing]
[narrator] December 15, 2020,
a satellite passing over Mt. Lemmon in Arizona
captures a group of mysterious structures
in the arid landscape below.
There's some very bizarre architecture going on here
in the Arizona desert.
There are two gigantic white domes,
and then there's also these pyramid-shaped buildings
connected with a central complex.
I've never seen anything like it.
[narrator] The isolated structures
cover an area of over 100 acres,
with each dome measuring 180 feet in diameter.
This looks like something out of a sci-fi movie,
like a kind of colony on some alien planet.
[narrator] To Anthony Morgan, the facility's unearthly appearance
may not be a coincidence.
[Anthony] The domes in our image look like
the Mars Desert Research Station.
That's where we conduct research trying to figure out
what it would actually take to live on Mars.
[narrator] Utah's Mars Desert Research Station
is one of the largest such facilities on earth.
Over the past two decades,
more than 1,000 people have spent time in isolation here
preparing for humankind's first attempt
to colonize the Red Planet.
An important part of knowing what it would take to live on Mars
is understanding not just your physical surroundings,
but the human psychology involved as well.
That's why this research station is built in the Utah desert.
It's a pretty close analogy to Mars.
[narrator] Local records confirm the structures in the image
are also dedicated to extraterrestrial science.
But their story is mired in controversy and recrimination.
These strange structures once witnessed
one of the most bizarre and incredible experiments
in human history.
[narrator] That history begins in the early 1980s,
the height of the Cold War.
With many fearing that a nuclear conflict
could soon lay waste to humanity,
a group of scientists and businessmen
hatch an extraordinary plan.
[George] They had this grand idea
to shuttle some elites off the planet
to basically repopulate other parts of our solar system.
[Linda] The vision was that if earth became a kind of nuclear wasteland,
some of America's elites
could be living on another planet.
[Guy] The problem was that man had only just set foot on the moon.
So, the idea of actually building a colony there
was a long way off.
So the concept needed to be proved on earth first.
And that's where this strange facility comes in.
[narrator] After years of planning,
construction on the $150 million prototype space colony
called Biosphere 2,
begins in 1987.
[Randy] The plan of Biosphere 2
was to see how well a self-contained biome
of different environments
would work as a colony on a different planet.
[George] It's called Biosphere 2,
because essentially Biosphere 1 is earth.
And this is an attempt
to create a miniature earth
under controlled conditions.
[narrator] To replicate our planet, scientists fill
the 7 million cubic feet greenhouse
with areas of marshland,
rainforest, savanna and desert,
and install a 1 million gallon mini ocean.
Sealed off from the outside world,
over 3,000 plant species generate the oxygen needed
for Biosphere 2's inhabitants.
[Adam] The two white domes are called lungs.
When the air expands it goes into the lungs
which have a flexible membrane
that can equalize the air pressure
between the lungs and the main building.
[Amma] This is really cool because you're able
to clean the air that is produced inside
and recirculate it.
[narrator] On September 26, 1991,
eight volunteers, four men and four women,
enter Biosphere 2.
The plan is to seal them inside for two years,
replicating a long space mission.
But after only a few weeks, things start to go wrong.
They say that an army marches on its stomach.
And that was the first problem.
[Adam] Food wasn't exactly abundant in Biosphere 2.
Different crops would suffer and die,
and then they would have no more of that crop to consume.
[George] One reason the crew's crops were failing
was because the population of bees that they had in them
were dying out.
The special design of the glass in the greenhouse
was disorienting them.
[narrator] While the bees die, cockroaches,
brought in to recycle organic matter, prosper,
and eat more of the remaining foodstuffs.
One of the few crops to thrive are sweet potatoes,
which the volunteers each consume
at the rate of one pound a day.
Eventually the residents of Biosphere 2
were eating so many sweet potatoes
that their skin started to turn orange.
But worse than that
is what happened with the facility's oxygen.
[narrator] As the oxygen-generating plants die,
bacteria living in Biosphere 2's soil
consume more of the precious gas.
Oxygen levels drop to 14%,
equivalent to living at Mt. Everest base camp.
[George] On top of all the health problems
people were having in Biosphere 2,
the organizers had started selling tickets to the public,
basically turning the experiments into a human zoo.
[narrator] As the experiment rolls on, these conditions
take a psychological toll on the volunteers.
Unsurprisingly, the residents became extremely agitated.
They split into two groups and started battling with each other.
Throwing things and spitting at each other.
Eventually the organizers of the experiment
realized that if they didn't step in,
something terrible was gonna happen.
And so they didn't end the experiment,
but they did start providing people with food and oxygen.
[crowd cheering]
[narrator] When the volunteers leave the facility in 1993,
many in the scientific community
mock the experiment and its organizers.
According to official reports,
Biosphere 2 subsequently closes.
But the latest satellite images reveal something strange.
This experiment was meant to have ended in the 1990s,
but this place still looks operational.
What's going on here?
Biosphere 2 is indeed still operational.
And it now has a new brief,
and that is saving the planet from catastrophe.
[narrator] Coming up, the subtropical time machine.
It's inspiring to see this huge facility
flipped around into something so positive.
[narrator] And the strange structures that helped to defeat Hitler.
They had to make sure they got it right
'cause they were only gonna get one chance.
[buzzing]
[narrator] This is Biosphere 2,
the site of a highly controversial experiment
to prepare humanity for life on another world.
Officially, the program ended in the 1990s,
but recent imagery shows renewed activity
at the structures.
What's going on inside these domes now
is some of the most important research
happening anywhere on earth.
[narrator] Government records reveal
the University of Arizona takes over the facility in 2011.
Its scientists repurpose the former pseudo space colony
and give it a more critical mission.
Today, this facility is dedicated to help humans
continue to thrive on a planet
that is increasingly suffering the effects of climate change.
Biosphere 2 is originally about escaping the earth.
Now, it's about saving it.
[narrator] While the theory of human-induced climate change
is accepted by almost all scientists,
many of the consequences it will have for life on earth
remain a subject of debate.
Researchers at Biosphere 2
are trying to solve some of these mysteries
and find solutions to many of the threats facing humankind.
[Linda] For scientists, Biosphere 2
is essentially a time machine.
They can use it to play out the things
that they predict might happen in the future,
and see the effects.
[narrator] One of the most visible effects of climate change
can be seen in coral reefs,
which scientists fear could disappear almost entirely
by the year 2050.
By adjusting conditions within Biosphere 2's ocean,
John Adams and his team
are trying to find species of coral resistant
to the impacts of our changing oceans.
We want to look at how corals are going to respond
not only to the changes in atmospheric CO2,
but also changes in temperature.
Can we breed a coral that is going to be more resilient
to future temperatures?
Scientists here are testing the idea of a super reef
by seeing which species survive best
under climate change conditions.
Studying how it reacts,
could hold the key to defending our oceans
against this unfolding catastrophe.
[narrator] Nowhere is this unfolding catastrophe
being more keenly felt than in the planet's rainforests.
Since the original experiment at Biosphere 2 was conceived,
humankind has destroyed an area of tropical forest
the size of Europe.
[Linda] This is an absolute catastrophe.
For the first time in history,
they're giving out more carbon dioxide than oxygen.
[Greg] Rainforests are home to roughly half
of the world's plant and animal species.
It's almost impossible to imagine
how our planet could function without them.
[narrator] The fear is that as global temperatures continue to increase,
trees will die in greater numbers
leading to even bigger temperature rises.
But research in Biosphere 2's rainforest
suggests there may be some hope.
[John] What's really unique about the Biosphere 2 rainforest
is that you can actually subject the entire tree
to a change in temperature.
Today, what we've been doing
is we've been heating our rainforest up
to look at what extreme temperatures are going to do.
[narrator] By cranking up the heat within the rainforest area,
Adams replicates predicted global temperature rises
over the next eight decades.
Surprisingly, and encouragingly,
the early results of these rainforest experiments
are showing that these plants, these trees,
are far tougher than we think.
The evidence seems to be that many
of the rainforest plants are more resilient
to rising temperatures than we had feared.
[narrator] Results from other experiments here are equally surprising.
This machine measures methane emissions
from trees in the rainforest.
[John] This is really cutting edge.
Methane is an extremely important greenhouse gas.
We still know very little about how it's produced
and what increases or decreases that production
in the natural system.
[Linda] As crazy as this may sound,
scientists have actually discovered that some trees
give off methane from their trunks.
And this is particularly bad in areas that are flooded in the Amazon.
What these trees essentially become are chimneys.
They're pumping greenhouse gas out of the earth.
Now that is catastrophic.
Why? Because methane is many, many times
more damaging to the environment than carbon dioxide.
[narrator] Thanks to the work of Adams and his team,
the strange structures revealed from space
have undergone an extraordinary transformation.
What was once a place of scientific ridicule,
is now playing a vital role in helping
to preserve our planet for future generations.
[Greg] It's inspiring to see this huge facility
that at one point was looking like it might be a failure
really flipped around into something so positive.
[narrator] Coming up...
[Guy] Sea team, they played a key role
in the battle that changed the course of human history.
[narrator] And building the impossible.
This was a daring and risky undertaking.
It was really groundbreaking.
[buzzing]
[narrator] January 5, 2022,
a satellite orbiting over the south coast of England
captures something strange lurking beneath the waves.
[Klint] It's really weird.
Where the land ends and the ocean starts,
we've got five sets of lines
and they have a very precise distance between them.
They look like they've been scratched into the terrain,
like fingers down a blackboard.
[narrator] There are 45 of the mystery structures,
some over 150 feet long.
[Samantha] It's a really interesting image,
but it's really unclear as to what these lines
going down into the sea actually represent.
[narrator] Historians think the location is significant.
[Mark] This particular island
is part of the complex of Portsmouth harbor,
which was one of the most important naval bases
through English history.
[Guy] Given the location, I'd say that these lines
must have had something to do with launching ships.
[narrator] Portsmouth rises to global prominence during the 16th century
when Tudor King Henry VIII embarks on a project
to vastly increase England's naval power.
Between 1509 and 1547,
he expands his fleet from five to 58 ships
triggering a period which sees England
explore and conquer vast areas of the world.
He increased it more than tenfold,
and many of those ships
were built here and launched here.
So it's just possible that these remains we see
were Tudor slipways.
[narrator] Historic records confirm
the mystery structures are slipways or boat launches,
but ones constructed long after the reign of Henry VIII.
These slipways were part of one of the largest
naval operations in modern history.
They played a vital role in D-Day
The plans for these slipways are drawn up in 1943
when Allied forces ramp up preparations
for a massive assault on Nazi-occupied France.
D-Day took over two years to plan.
And the Allies knew that a swift surprise attack
from a massive and carefully coordinated fleet
was the only way to push their way
into continental Europe.
[narrator] Military planners identify
Normandy's wide beaches as the ideal site
for a surprise amphibious assault,
but their bays are too shallow
for traditional troop-carrying ships.
One of the keys to D-Day for the Allies is getting
as many troops and tanks and artillery pieces ashore
as quickly as they can, ready to fight.
[narrator] In response, military chiefs commission
around 4,000 flat-bottom landing craft
using the area in the image as their base.
Landing crafts are the centerpiece of the operation.
Without these ships
our troops would never get near the coast of Normandy.
[narrator] Ahead of the biggest amphibious attack in history,
Allied forces carry out rehearsals
designed to mimic the conditions of D-Day.
The logistics and planning that went into preparing for D-Day
are absolutely mindboggling.
No amphibious assault on this scale had ever been attempted,
and they had to make sure they got it right
because they were only gonna get one chance.
[narrator] One such rehearsal in April 1944,
code named Exercise Tiger,
cruelly highlights the potential for disaster.
As 30,000 Allied troops storm a beach in Southwest England
patrolling Nazi E-boats open fire,
inflicting massive causalities.
In the subsequent chaos 946 soldiers die.
[Samantha] Exercise Tiger is catastrophic,
American and British soldiers are dying here and they haven't even left Britain.
[narrator] On June 6th, 1944, more than 6,000 ships and landing craft,
many launched from the area seen from space,
carry more than 150,000 troops onto the Normandy beaches.
To sustain the ferocity of the assault, damaged ships are returned to the site,
hauled out of the water sideways, repaired,
and quickly returned to action.
[Sascha] Every ship available had to be kept in continuous operation
in order for the invasion to succeed.
These slipways were a critical part of that rapid return to action
and thrown back into combat against a determined enemy.
[narrator] Over the following weeks the slipways help land 2 million soldiers,
400,000 vehicles, and 3 million tons of supplies onto the French beaches.
And the tide of war turns forever.
[Guy] These strange underwater lines
may not seem like a vital piece of military equipment,
but actually they played a key role in the battle
that changed the course of human history.
[narrator] Coming up, a century old mystery emerges from the depths.
It is not something you would expect to see in the middle of Lake Superior.
[narrator] And the WWIII mega weapon.
You drop one of these and everything stops.
[narrator] March 28th, 2022,
a drone scans the seemingly endless expanse of Lake Superior,
the largest of the Great Lakes.
As the camera passes over its Northern shores
it spots something strange.
I'm looking at an expanse of blue water
with an island,
but all these shapes in the water are really puzzling.
There's a lot of straight lines and some type of structure
beneath the surface of the water.
You don't really see something like this very often.
[narrator] The island is one of around 400
that dot this 31,700 square mile body of water.
The shapes in the water here are just extraordinary.
It is not something you would expect to see in the middle of Lake Superior.
[narrator] Analysts study the submerged shapes in more detail.
When you see strange shapes like this underwater
the first thing that comes to mind is that it's a ship wreck.
[narrator] Lake Superior has been used by mariners to trade goods
between Canada and the US for around 10,000 years.
In the 17th century the number of ships on its waters explodes,
as hunters ravage the region for wolf, bear, and beaver pelts.
[Patrick] The fur trade is really critical
and trappers depended on the transport these Great Lakes provided.
[narrator] By the 19th century
around 2,000 ships are crossing the lake each year.
Many do not survive the perilous journey.
Lake Superior literally has a stretch called Shipwreck Coast
because so many ships met their ends there.
[Guy] It's possible that there structures
are therefore something to do with Lake Superiors, really,
pretty horrific legacy of ship wrecks and maritime destruction.
[narrator] Yet, when analysts turn to historic records of the island
they discover the strange shapes have a very different origin.
Looking at 19th century records, we discover that this tiny island
was the location of the richest silver mine
in the entire Western Hemisphere.
[narrator] Lake Superior's Silver Rush begins in the American Civil War.
To finance its campaign against the Confederate States,
the Union prints large amounts of paper currency.
Distrustful of this new form of money,
many Americans hoard reserves of gold and silver, causing prices to soar.
In the 1860s silver prices reached an all-time high.
Anyone looking to make serious money
is now scouring the New World for precious metal.
[narrator] In May 1868, prospects from The Montreal Mining Company
find silver nuggets on the island in the image.
They soon discover that the reef
sits on a massive vein of the metal that stretches deep under Lake Superior.
This is an opportunity for entrepreneurs to come along, invest,
and make a lot of money.
[Guy] But accessing it meant doing something
everyone thought was impossible,
building an underwater mine.
[narrator] To access the sliver,
engineers construct breakwaters
allowing them to increase the islands size tenfold,
creating the strange patterns in the image.
They then dig mine shafts up to 1,250 feet deep,
greater than the height of the Empire State Building.
The ideas pioneered to allow this mine to function were utterly groundbreaking.
This mine isn't just underwater,
but it's under the choppy waters of Lake Superior.
[narrator] The next problem the company faces
is finding people brave enough to work in a damp, freezing mine
surrounded by Lake Superior's crushing waters.
This is probably one of the absolute worst environments
that anyone could ever hope to mine in.
[Patrick] If that mine shaft was flooded
there's no way out,
you're dead.
[narrator] Over the next decade or so the miners extract the equivalent
of $78 million worth of silver from the lake bed.
Despite these insanely difficult and dangerous conditions,
it's digging up millions of dollars' worth of silver every year.
[Samantha] It really is incredible to see just how far people will go
if there's a chance of getting rich.
[narrator] The mine continues to operate until 1883,
when a storm prevents a vital shipment of coal from reaching the island.
Without the coal the pumps stop working,
and water comes flooding in,
destroying the mine's structure and filling the tunnels again.
[narrator] Over the next 140 years, the freezing waters of Lake Superior
reclaim the rest of the mine.
Today, all that remains is its ghostly outline,
the forgotten dreams of long buried treasures.
It's certainly possible that there is a lot more silver under Lake Superior.
So if you've got a scuba suit and unlimited courage, you can always give it a shot.
Coming up, the mystery of Anthrax Island.
There's really no telling what secrets could be hiding there.
[narrator] And the color changing cauldrons.
Local people here worship and venerate these lakes as places of the dead.
[narrator] May 21st, 2021,
as a satellite passes above the West Coast of Scotland
it captures something weird on an island far below.
[Samantha] Looking at this ariel photograph of the Outer Hebrides,
there is this very clear, distinct
form in the landscape.
This is bizarre because it looks like a perfect circle
with another perfect circle around it.
[narrator] The mystery shapes measure over 12,000 feet in diameter.
The perfection of the circles is phenomenal.
It's almost like a gigantic watch face imprinted on the Earth.
[narrator] The giant circles sit close to a cluster of isolated structures.
[Lindsay] You can tell that these aren't residential,
this strikes me as some sort of official complex,
like a government run facility.
[Guy] The questions is, why would the government be interested
in this remote area of land in the Outer Hebrides?
[narrator] Government records reveal that this part of Scotland
has long been a center for clandestine military research.
During WWII the British Government chose the Hebrides
for a series of highly controversial tests.
It's entirely possible that this location is connected to those tests.
[narrator] The test program begins in 1941,
a time when the fate of Europe is on a knife edge.
With Hitler's forces amassing across the English Channel
Prime Minister Winston Churchill
steels his country for a Nazi invasion.
[Carlos] Now, above all else, the government wanted to be absolutely sure
that in the case of an invasion
the British would have some sort
of counterattack plan in place.
[Samantha] Churchill was gonna do whatever it took,
and so the British Government
is looking to all of its options,
including biological warfare.
[narrator] As part of a program
code-named Operation Vegetarian,
Churchill instructs a team of scientists to work on a plan
to bombard German cattle with feed laced with anthrax.
By wiping out millions of cows,
they hoped to cripple the country by causing a nation-wide famine.
What the British Government wanted was a reprisal of epic proportions
should the need ever arise.
Now, what they were looking for was a total collapse
of German infrastructure.
[narrator] As a test run, scientists on an island in the Outer Hebrides
dropped anthrax bombs on a herd of sheep.
[Samantha] Many sheep are sacrificed in this experiment.
But more importantly,
the landscape itself was poisoned for years afterwards.
It was so bad that it earned the nickname The Island of Death.
[narrator] Military historians discover that the site in the image was indeed used
for developing weapons of mass destruction,
but ones from a later period in history.
[Guy] This circular structure is actually linked to a type of weapon
that could've had far more devastating consequences than anthrax
and in far less time.
This was a nuclear testing facility for the CORPORAL Missile.
[narrator] The story of the CORPORAL Missile begins in 1944,
when Germany starts terrorizing London with its V-1 flying bomb.
Spooked by its revolutionary capabilities,
Washington launches its own long-range weapons program.
America was desperate to develop the technology that the Germans had.
And as a result, the idea of creating a missile
on which a warhead could be attached becomes a priority.
[narrator] In 1944, US engineers soon begin tests
on a series of liquid-fueled, gyroscopically-guided rockets.
Following the Soviet Union's first successful atomic test five years later
the military accelerates the program developing the CORPORAL,
a 46-foot long missile armed with a 1,500 pound nuclear warhead.
This is the first guided missile with a nuclear warhead attached.
And you're looking at more firepower
than most battlefields in WWII ever saw.
[narrator] At this time in history,
one of America's, and its allies greatest fears,
is a Soviet land invasion of Western Europe.
Outnumbered 3-1 by Stalin's troops and tank battalions
the US turns to the CORPORAL Missile to even up the odds.
[Guy] The CORPORAL was a tactical weapon rather than strategic.
Now, that means it was designed for use on the battlefield
against an approaching enemy.
If you are faced with an overwhelming force,
you drop one of these and everything stops.
[narrator] In 1954, Britain, a possible last line of defense
on a WWIII battlefield, purchases the CORPORAL Missile system,
and then installs it at the site in the image.
There's a sense that Britain needs to protect itself.
It is, after all, far closer to a Soviet enemy than the United States.
[narrator] Soviet-era documents reveal that the Kremlin's plan
was to specifically attack sites,
like the one seen from space, should war break out.
[Guy] Of course, thankfully, the Cold War never escalated
to the extent that many feared.
And the CORPORAL was ultimately never deployed in a war.
[narrator] The site in the image continues to be used to military tests,
but their exact nature remains classified.
There's really no telling what other government secrets could be hiding there.
[narrator] Coming up, windows into the underworld.
The lakes seem to be changing color,
I have no idea what's going on here.
[narrator] October 6th, 2021,
eyes in the sky over the Indonesian island of Flores capture this image.
This is mind-blowing, you've got these three lakes
and what's weird is, they are dramatically different colors.
[George] The colors in this satellite image are astounding.
They look really beautiful, like an artist's palette for painting a portrait.
[narrator] When analysts turn
to Maxar SecureWatch Technology the mystery deepens.
As I scan back in time it gets even weirder.
The lakes seem to be changing color,
I have no idea what's going on here.
[Anthony] What's really strange is they seem
to change independently of one and other,
and there's not an obvious catalysis.
[narrator] Geological records shed more light.
[Adam] These lakes sit on top of Mount Kelimutu which is an active volcano.
I think the strange shifting colors
might have something to do with activity deep below the surface.
[narrator] For those living nearby, these volcanic forces
hold deep, spiritual significance.
The local people here worship and venerate these lakes as the places of the dead.
They believe that the spirits of people go to specific lakes
depending on how you lived your life,
or the age that you were at the time that you died.
[narrator] The island in the image, and the rest of Indonesia,
sits on the Ring of Fire
a 25,000 mile long string of seismic sites
which is home to 3/4 of the world's active volcanoes.
For scientists, the color changing lakes offer a unique window
into the inner workings of these unpredictable forces of nature.
[Devin] From the bottom up,
a volcano is so much more complex than most people believe.
It's very hard to study because the heat and pressure down there would destroy
any instruments you lower down.
[narrator] Scientist speculate that each of the lakes in the image
is connected to sources of volcanic gases
by a complex network of vents called fumaroles.
Seismic forces mean this subterranean plumbing system
is always in a state of flux,
so different amounts of gases rise up through the volcano at any given time.
[Devin] We get this very complex feeder network
and that feeder network is constantly changing,
through pressure, and temperature.
Every time the volcano's uplifted one will close off and another one will open.
As those gases percolate up through the mountain they take different paths,
and they bring with them different minerals and different nutrients.
And they become isolated from each other in these craters.
[narrator] The constantly changing fumaroles feed various gases
and minerals into the lakes, changing their color.
Sometimes the chemistry changes
and the color of the lake changes almost instantaneously.
One lake may be more blue or more green depending on the amount and the type
of gas coming off the magma below.
[narrator] It also appears that Indonesia's frequent
rain storms affect the chemical cauldrons at the volcano's summit.
[George] One lake goes from a bright cyan blue during the dry season,
to a darker blue during the wet season,
and the black lake does the exact opposite.
[Devin] During wet seasons more oxygen's available to dampen those colors down.
And during the dry season they're really vivid and bright
because the oxygen levels are low.
[narrator] For scientist, predicting when the lakes change color
is more than just an academic question,
it could also save lives.
[Adam] In the last decade we've seen white plums arising from one of the lakes,
it is possible that Kelimutu is overdue for another eruption.
[Devin] This much gas churning through this volcano,
it's got to indicate it's due to erupt again,
we just don't know exactly when.
[narrator] The volcano last erupted in 1968,
raining steam and ash down onto surrounding villages.
Experts continue to try to decode these harbingers of disaster
from the skies before it's too late.
If we can't fully understand the indicators that these lakes provide us,
then we might miss signs of impending catastrophe.