Original subtitles

NARRATOR: They're watching you.

More than 6,000 satellites circle the Earth.

Every day, they uncover new, mysterious phenomena

that defy explanation.

Revealed from space,

the mystery of the stolen space shuttle.

WALTERS: What we're looking at is one of

the strangest incidents of the entire Space Race.

NARRATOR: The ghost fleet of the Devil's Sea.

What's strange is that this fleet

is moving towards the shore.

NARRATOR: And attack of the killer mega bugs.

This problem is out of control.

NARRATOR: Baffling phenomena, mysteries from space.

What on Earth are they?

[theme music playing]

April 12th, 2021.

As an orbiting satellite passes over

the central Asian country of Kazakhstan, it captures a weird

25-square-mile compound in the desert below.

This facility, whatever it is,

is absolutely vast, and it actually appears to

be being swallowed up by the landscape.

ANTHONY MORGAN: It doesn't look like

this is somewhere that people spend their time.

The structures around it, they look dilapidated.

NARRATOR: What really intrigues analysts is something

in the middle of the compound.

There's this massive structure.

I've never seen anything like it.

What's really weird about it is the triangular

sort of shape.

It really looks like some sort of spaceship.

NARRATOR: Hooked by the weird structure seen from space,

a team of Dutch urban explorers is traveling

across Kazakhstan.

Ah.

NARRATOR: To reach their target,

they must cut a path through the Kazakh Steppe,

a 300,000-square-mile belt of dry, featureless grassland.

NARRATOR: Kazakhstan has one of the lowest population densities

on Earth,

and it has a dark history,

one that could explain

the desolate compound captured from above.

RODRIGUEZ McROBBIE: Given this facility's location,

its isolation, it's quite likely

that this is connected to Soviet-era

experiments in the country.

NARRATOR: During the Cold War,

Kazakhstan is one of 15 Socialist Republics ruled over

by the Soviet Union.

The Soviet rule of Kazakhstan was kind of

characterized by a lot of highly controversial

nuclear testing.

And in order to conduct these tests,

the Soviets created these massive facilities

in Kazakhstan.

One of the goals was to keep it secret.

They didn't want their enemies to know about it,

but that meant they kept it secret from the local

population, as well.

[button clicks]

[explosion blasts]

NARRATOR: Officials claim the test sites lie

in uninhabited parts of the country.

In reality, more than a million people live nearby.

What's more, the Soviets used them as human

guinea pigs to study the effects of nuclear fallout.

RODRIGUEZ McROBBIE: What made the tests even more deplorable

was the fact that the Kazakh people were unwitting

test subjects.

They didn't know they were being

exposed to huge amounts of radiation.

What the Soviets did at these sites, and I don't

think there's any other word for it, is basically evil.

NARRATOR: If the site in the image is a relic of Soviet rule,

the explorers fear it could be monitored,

so they ditch their car and continue on foot.

NARRATOR: As the site appears in the distance,

it becomes clear their fears were justified.

[gunshots blasting]

[bleep]

NARRATOR: The team waits until nightfall before proceeding,

hoping darkness can cover their approach.

NARRATOR: Armed guards aren't the only

obstacle in their path.

NARRATOR: The team reaches the site with

only a few hours darkness remaining.

NARRATOR: The explorers navigate their way towards

the giant buildings in the image.

[exhales heavily]

[bleep]

WALTERS: This building is just like a massive cathedral,

and right in the middle of it

is this really odd-looking machine.

NARRATOR: The explorers have made

a discovery that appears to defy explanation.

I'm not too sure that it's sitting

in the right place, frankly,

because we're in the middle of the Kazakh desert.

It looks to me like a space shuttle.

NARRATOR: At just over 100 feet long and with swept back wings,

the shape of the craft is unmistakable.

It's a weird yet pivotal legacy of the battle

to conquer space.

This thing is the result of the biggest

and most expensive project in the history of

Soviet space flight, but it has been sitting in

this hangar gathering dust for decades.

NARRATOR: Declassified Soviet files reveal it took more than

a million people to design the craft

at a cost of $26 billion.

RODRIGUEZ McROBBIE: Despite costing huge amounts of money

and years to complete, the craft only made one mission.

But that's not the really strange thing about it.

WALTERS: The story behind this machine is

a combination of revolutionary engineering and absolutely

audacious spycraft.

NARRATOR: Coming up -- space wars.

They were convinced that it could nuke Moscow.

NARRATOR: And dragons of the Devil's Sea.

KOUROUNIS: There are tales of them attacking

ships and dragging sailors to their doom.

NARRATOR: Lured by a giant desert compound in Kazakhstan,

a team of urban explorers has

discovered a rusting multi-billion dollar spacecraft.

WALTERS: What we're looking at is the forgotten relics of

one of the strangest incidents of the entire Space Race.

NARRATOR: That incident has its origins in the early 1970s.

The Soviet Space Agency, still smarting from the success of

the Apollo 11 mission,

learns that NASA is working on a revolutionary new craft,

one that it fears could land a killer blow in the Space Race.

MUNOZ: The Soviets get information that

the United States is working on

a new winged space aircraft,

what would eventually be the space shuttle.

WALTERS: The concept of the space shuttle

absolutely terrified the Russians.

Many of them felt it could have totally swung

not just a Space Race, but the entire Cold War in

America's favor.

OVER RADIO: Standing by now for solid rocket booster

separation confirmation.

NARRATOR: What scares the Soviets is that,

unlike their craft, the shuttle can reenter

the atmosphere and fly down to any point on Earth.

NASA claimed that the shuttle was all about science,

but the Soviets didn't buy it.

They were pretty convinced that it could be used for

nefarious purposes,

like maybe to fly down and nuke Moscow.

The head of the military approaches Soviet leader

Leonid Brezhnev,

and tells him that he needs to do something about this

potential threat, and he needs to do it fast.

NARRATOR: Brezhnev immediately orders the KGB to

begin spying on the shuttle program.

To its astonishment, the security agency discovers

that many of NASA's plans,

including detailed blueprints, are in the public domain.

The Soviets couldn't believe their luck.

This is a country where people's lunch orders are

classified, and here NASA

had gifted them the plans for the world's most

advanced spacecraft.

WALTERS: But even though the designs were made public,

the Soviets still had a big problem.

There was reams and reams of material,

thousands and thousands of documents, and they were spread

through dozens of departments.

NARRATOR: The Soviets reportedly set up fake research centers to

purchase and funnel vast amounts of NASA data to Moscow.

When the U.S. government begins storing its data online,

it forces the KGB to turn to hacking

to garner yet more intel.

[dial-up internet squawking]

I mean, they steal anything they can get

their hands on related to the space shuttle program.

This is possibly the first case

of internet espionage in history.

By doing this, the Soviet Union

saves billions in research and development costs.

NARRATOR: Over the following years,

1,200 companies use the stolen plans to

secretly build a kind of space shuttle 2.0.

The Soviets call their craft

the Buran, Russian for snow storm.

But the Kremlin's long campaign

of espionage has not gone unnoticed.

MORAN: The CIA gets wind

of what the Soviets are up to and starts

feeding them faulty

and fake upgrades that they hope the Soviets will

incorporate into the development of the Buran.

MORGAN: They would change things like the heat shielding

on the outside of the shuttle.

That is really important, because as you reenter

the atmosphere, it risks exploding.

NARRATOR: Despite the CIA's attempts to undermine

the Buran program, by 1985,

the Soviets have begun atmospheric test flights.

It's easy to look at the Buran and think

that it's just a carbon copy of the space shuttle.

But it actually included a number of really

clever designs that were 100% Russian in origin.

MUNOZ: All the mechanics and all the electronics were

Soviet designed, but the biggest thing was that

you could fly on automatic mode,

which means it didn't require a pilot.

NARRATOR: The Soviets choose the site in the image,

Baikonur Cosmodrome,

to showcase their new space plane to the west.

What you're looking at here is in

effect the birthplace of the Space Race.

It's where the Soviet Union launched

the first satellite put in orbit.

[satellite beeping]

It's where the Soviets launched Yuri Gagarin,

the first human being to orbit the Earth.

So this is a historical site for humanity.

NARRATOR: At six a.m.

on November 15th, 1988, a Buran launches from Baikonur

before successfully completing a 3.5-hour unmanned flight.

It will prove to be its only mission.

The Buran was, in many ways, an amazing achievement.

Let's not forget that.

But unfortunately, it did suffer from bad timing.

By the time it was ready to launch,

the Soviet Union was already imploding.

MUNOZ: The Kremlin had other priorities,

so the program lost political support,

and eventually, it lost its funding.

Today, two remaining Buran lie forgotten

and gathering dust in Kazakhstan,

weird relics of one of the most daring heists

of the 20th century.

It's fitting that we're able to look down from space

and see something that, albeit bizarre,

played such an important role in the history of

space exploration.

NARRATOR: Coming up, ghosts of Iwo Jima.

WALTERS: They appear to be rising out from

the ocean and trying to get onto the land.

And the swamp cipher of the Congo.

There's so many questions about this really

strange image.

NARRATOR: January 26th, 2022.

A satellite scans a remote

archipelago 750 miles southeast of Japan.

The image shows a coastline, and right

along the division between water and sand,

there's this line of what looks like mangled ships.

I count at least seven pointed bow sections.

These are hulking, great pieces of

what must have been a sunken fleet.

Further analysis using Maxar's

satellite imagery deepens the mystery.

I built a time lapse, which shows images

over the years between 2009 and current day.

It's amazing.

As we roll forward,

The ships appear to be moving and coming into the shore.

NARRATOR: The ghost fleet's location intrigues analysts.

It sits in an area known as the Dragon's Triangle.

The waters in this area have been called

the Pacific Ocean's answer to the Bermuda Triangle.

This is a part of the Pacific known for very,

very unexplained, mysterious disappearances of ships

and boats.

NARRATOR: Reports of disappearances in these waters

date back to before 1,000 BCE,

the same time that dragons begin to appear in

Asian folklore.

According to Chinese fables,

dragons would live in the waters here, and there are

tales of them coming to the surface and attacking ships

and dragging sailors to their doom.

NARRATOR: Over the past millennia,

the Dragon's Triangle has claimed thousands of vessels,

including entire fleets.

Perhaps what we're seeing in the image is casualties

of this mysterious force rising from the deep.

Martin Morgan studies the ghost fleet in more detail.

On closer examination of the wrecks,

something that jumps out is the fact

that these are not old wooden wrecks.

This isn't something from ancient history.

This is something from recent history.

NARRATOR: Morgan believes the fleet is the legacy of one

of the most brutal conflicts of the 20th century.

The island where these wrecks are pushed

ashore is an island that's called Ioto,

but it used to be called Iwo Jima.

NARRATOR: The strategically vital Iwo Jima becomes

the focus of U.S. naval might

in October 1944.

The United States wanted to capture Iwo Jima

to establish it as a base.

It would provide fighter coverage for the bombers

as they moved on toward targets in the Japanese home islands.

NARRATOR: On February 19th, 1945,

more than 450 U.S. ships unleash a devastating assault

on the island.

70,000 U.S. Marines invade but are

hampered by the island's treacherous sandy terrain.

MARTIN MORGAN: The battle of Iwo Jima ended up being

a brutal battle, and that's because of

the slow, plodding progress,

the attritional action that characterized the fighting.

NARRATOR: 36 days of hellish combat claim over

27,000 American and Japanese lives.

Yet while the U.S. emerges victorious,

its mission is far from over.

The intention was to create this large, artificial

naval base right here in preparation

for the eventual planned assault on mainland Japan.

Iwo Jima has no natural harbor of any kind.

So one had to be created, and the shipwrecks that

we're seeing were a part of that plan.

NARRATOR: To create the harbor's breakwater, Navy engineers

scuttle 24 ships close to shore.

These enormous ships were being lined up in a rectangular

shape and with an opening to let supplies and soldiers in,

You know, what it's doing is to form this perfect barrier to

powerful ocean waves and all those currents.

NARRATOR: Eight decades later, those same ships

mysteriously emerge from the depths.

A photograph taken following the U.S. victory all those years

ago offers a bizarre clue to explain how.

WALTERS: That photo of those six soldiers

hoisting that American flag

became one of the most reproduced pictures in history.

This famous photo was actually taken at the summit of

Mount Suribachi, which is considered

one of the most dangerous volcanoes in the world.

Mount Suribachi and the island sit

on the Pacific Ring of Fire,

a 25,000-mile belt of volcanoes.

The massive tectonic forces mean the seabed

can rise up to 30 inches a year.

DENNIE: As magma works its way up underneath the island of

Iwo Jima, it actually can tilt or bow the rock upward,

and the entire surface can raise up.

In fact, the beach that the U.S. Marines

landed on back in 1945 is now

50 feet above where it was the day they landed.

NARRATOR: Over time, the buildup of magma

forces the ships onto shore.

The amount of volcanic activity here could also shed

light on other historic events in the Dragon's Triangle.

KOUROUNIS: Undersea volcanic eruptions

can be tremendously violent,

shooting these rooster tails of debris and rocks

and water hundreds of yards through the air.

It makes sense -- lava being spewed from under the sea

connects directly

with the idea of a dragon breathing fire

and swallowing whole ships.

NARRATOR: Today, the Iwo Jima ghost fleet

continues to rise from its watery grave,

a unique memorial to those who

perished here all those years ago.

It's like the earth is giving us back

a piece of history, rather than taking it away.

NARRATOR: Coming up, the monsters eating America.

If we don't have the means to detect and stop

these creatures, this could lead

to even more disastrous situations.

NARRATOR: And the desert ice fortress.

The oddest thing is that it's

the opposite of what we would expect.

NARRATOR: March 20th, 2021.

A survey plane scans the Catskill Mountains in

the northeastern United States

using sensors to detect what the human eye cannot.

They have really clever instruments that can measure

near infrared light and tell us

how green a forest's trees are.

NARRATOR: When the images are processed,

red colors represent dense, healthy vegetation.

What's unusual is these small patches of gray

and white, which appear to look like ghostly trees.

RUBEN: Across thousands of acres,

we see countless individual trees losing their color.

The fear is that these trees

are dying -- or worse, are already dead.

NARRATOR: It's not just the scale

of the devastation that worries analysts.

What's even more concerning is that

it's actually just one species that's affected.

It's the eastern hemlock tree.

NARRATOR: The eastern hemlock, a pine evergreen, can grow

to 100 feet tall and live for 1,000 years.

They cover more than two million

acres of the eastern United States.

RUBEN: They have an amazing ability to store carbon

and absorb tons of water,

which slows the melting of the winter snowpack

and can make floods less severe.

If all these hemlock trees disappeared,

it would be really disastrous.

NARRATOR: Local historic records could offer a clue

to the mass death revealed from the skies.

AUERBACH: Looking into this region's history,

I wonder if there might be a connection between this

and the hemlock tree's role in a once thriving industry,

leather tanning.

NARRATOR: In the first half of the 19th century,

tanneries spring up across

the Catskills to clothe and shoe the waves of immigrants

arriving in New York.

It's a bloody, brutal industry, and one which relies on

the hemlock's thick bark.

AUERBACH: It was really, really tough work.

They used axes to fell the trees and special tools

called barking irons to remove the bark

from the trees themselves.

The bark of the hemlock tree contains an acid that's easy to

extract when you soak it in water.

Applying this acid solution to raw animal hides fuses

the protein fibers, which produces usable leather.

NARRATOR: The Catskills tanneries are known to

have stripped some 70 million hemlocks.

But Roland Kays reveals the trees in the images

are casualties of a different kind of destructive force.

These ghostly trees are the victim

of an invasive insect.

Eastern hemlocks are known to be vulnerable

to a specific type of invading insect --

the hemlock wooly adelgid.

NARRATOR: These tiny insects gorge

on hemlocks in their billions,

releasing a toxic saliva, which slowly kills their host.

These adelgids suck sap from the hemlock's

twigs and needles, disrupting the flow of water

and important nutrients for the tree.

They're called a wooly adelgid,

because after they feed on the sap,

they exude their excrement, basically, as this sort of

white, waxy substance that looks kind of like wool.

NARRATOR: Within four years,

a swarm of the tiny insects can kill a tree that began life

before the arrival of Christopher Columbus.

In the lifespan of a tree, that's a pretty quick death.

All the while, the adelgids of reproducing and spreading

new generations of bugs

into neighboring trees and basically spreading

the destruction throughout the forest.

NARRATOR: Wooly adelgids are alien invaders,

having been accidentally smuggled in

from Japan during the 1950s.

Once they reached our forests,

they were able to spread unimpeded.

RUBEN: Experts have now spotted

the adelgid in at least 17 states,

and it's laid waste to millions of trees.

This problem is out of control.

NARRATOR: The hemlock isn't the only tree in peril.

Over the past century,

some 450 other species of insects

have decimated U.S. woodlands.

Every decade,

they eat their way through enough forest

to cover Florida almost twice over.

They don't just threaten our trees.

They can also impact our food supply and our homes.

NARRATOR: While adelgids feast on our forests,

thousands of our homes are now under attack from a species of

Chinese termite,

causing more than $1 billion dollars in damage each year.

One big colony of termites can threaten the structural

integrity of your house before you even know it.

NARRATOR: Perhaps the greatest threat these invasive bugs pose

is to agriculture.

Each season, pests ravage around 40% of U.S., crops.

SCHUTTLER: There's a fruit fly from

southeast Asia called Drosophila suzukii.

This insect has serrated hind quarters that can cut

into ripening fruit, and it lays its eggs inside.

RUBEN: When the eggs hatch, the larva will eat

their way out from the inside of the fruit.

It's impossible to tell which fruits have been affected,

and it often doesn't spoil until it's reached

its destination.

NARRATOR: Each year, Federal agencies spend

billions of dollars on eradicating

the bugs that are eating their way across America.

But the killer swarms show no sign of stopping.

If we don't have the means to detect and stop

these creatures, this could lead

to even more disastrous situations.

NARRATOR: Coming up, impossible engineering

in the ancient world.

OKEREKE: Large quantities of ice in blistering climates.

It was almost a miracle.

NARRATOR: And the mystery of the jungle labyrinths.

Who or what would create these shapes

in the middle of the Congo?

NARRATOR: January 2017.

A satellite passing over the vast desert

interior of Iran scans the city of Kashan

and captures this image.

This is definitely unusual.

OKEREKE: This looks like a large, barricaded plot

of land, almost like a circular great wall.

NARRATOR: The giant barrier is 2,000 feet

in circumference and around 50 feet thick.

And it conceals something unusual.

When we zoom in, we see these two domes,

and there's no clue as to what these are.

It looks very strange. It looks odd.

NARRATOR: Analysts turn to local records.

It appears the giant structure is the legacy of

a fearsome group of warriors who once ruled these lands.

It's likely that this was built

by people known as the Seljuks.

The Seljuk Dynasty ruled Central Asia

and the Middle East from the 11th to the 14th centuries.

NARRATOR: The Seljuks begin life in

the 8th century CE as a nomadic Mongolian tribe,

yet they soon develop a hunger for war and conquest.

Over the following centuries,

they move west amassing a vast army, which, in 1071 CE,

defeats the mighty Byzantine Empire.

[shouting]

They later went on to control Persia,

Iraq, and Syria, and that's when they really

established themselves as the Seljuk Empire.

NARRATOR: By 1092 CE, the Seljuks control

more than 1.5 million square miles

of Central Asia and the Middle East.

Its rulers accumulate

huge wealth from the 4,000-mile-long

Silk Road, which runs through the heart of their lands.

They built numerous forts, similar to what we see in

the images, to help protect caravan traders while they

traveled the Silk Road.

Seljuk fortresses are called caravanserai, fortified

rest stations spread exactly one day's travel apart.

There were places to stop, to trade,

to eat, and to take shelter from the elements.

Could this ring structure

we're looking at be the perimeter ring

of a caravanserai?

NARRATOR: Yet what puzzles experts is that

the strange domes within the giant wall

don't correspond to Seljuk military architecture.

Closer analysis offers a clue.

Zooming in on the image of

these two domed structures,

we see at the very top, a hole.

I think what we're looking at is a key characteristic

of an ancient engineering marvel

called a yakhchal -- it's an ice house.

NARRATOR: Yakhchals are a wonder of ancient engineering

which first appeared in Persia some 2,500 years ago.

OKEREKE: Yakhchals were basically early refrigerators.

These were huge structures that can chill

large quantities of ice in blistering climates.

NARRATOR: The yakhchal's 6-foot-thick insulating mortar

enables ice to be stored deep into the summer months,

extending the shelf life of food 100-fold.

They were made with a unique water- and heat-resistant mortar

that was composed of materials,

thought to include things like egg white,

clay, lime, ash, and even goat hair.

KOUROUNIS: Food preservation is of critical importance.

The best way to keep it fresh was to keep it cold.

NARRATOR: Yakhchals enabled desert people to

keep fresh food all year round.

But incredibly, they can also be

used to make vast amounts of ice --

not easy when temperatures regularly

hit 100 degrees Fahrenheit, and rainfall is rare.

How did they get water into

the heart of the desert in the first place?

Well, they had an ingenious solution to that problem,

and it was called the qanat irrigation system.

NARRATOR: Qanats are underground canals that carry cold water

from mountains up to 40 miles away

into pools located next to the yakhchal.

After sunset, water in these pools radiates so much

heat that ice can form in above freezing temperatures.

KOUROUNIS: And so, on these clear starry nights,

the water at the surface would cool

just enough to get below freezing point.

There would be ice to harvest before sunrise.

It was almost a miracle.

This is a demonstration of understanding your environment

and using that knowledge to your advantage.

NARRATOR: While yakhchals provide Iranians with

an endless supply of ice for over 2,500 years,

Europeans never developed this technology.

Instead, during the 19th century,

they begin importing it thousands of miles across

the Atlantic.

Demand is such that ice becomes the second largest

American export after cotton.

The market began with scientists who wanted the natural ice to

preserve things like medicines.

It quickly expanded to cafes and restaurants who

wanted iced drinks to sell to their clients.

Once people tried this new fad of cold drinks,

they never wanted to go back

NARRATOR: In the 1920s, the introduction of the domestic

refrigerator freezer

sounds the death knell for this bizarre

ice harvesting industry.

Yet even today, yakhchals can be found

across the Middle East,

continuing the incredible story of ice that began in

the sweltering deserts of Iran.

It blows my mind how they were able to come up with

this technology so many thousands of years ago,

whereas today, we completely take ice for granted.

NARRATOR: Coming up,

cracking God's code.

KAYS: These shapes pop up in all

sorts of unexpected places in nature.

NARRATOR: March 2022.

A satellite passing over the southern African country

of Zambia captures an image that continues

to puzzle experts.

It's really easy to miss what's so mysterious

about this photo at first glance,

but once you look closely, you notice the carved spirals

in the earth below.

It's really strange.

There appears to be at least three

large spiral curlicue patterns.

They don't seem to lead anywhere.

They spiral outwards and then just stop.

NARRATOR: The weird shapes lie in

the 1.4-million-square-mile Congo Basin,

one of the largest,

most pristine rainforests on the planet.

There's so many questions to ask about this

really beautiful but strange image.

I just don't know who or what would

create these shapes in the middle of the Congo.

NARRATOR: A possible clue can be found

7,000 miles away in the deserts of South America.

Just take a look at the Nazca Lines in Peru,

the famous Nazca Lines.

Now, they feature a giant representation of the monkey.

And if you look at his tail, that tail is a perfect spiral.

NARRATOR: The purpose of this 2,000-year old

animal geoglyph is unclear,

but some believe it served a religious purpose.

And the people who live near the Congo spirals

are also known to venerate the beasts of their jungle.

This region is home to a people called the Hemba.

When you look at the history of the culture of

the Hemba, what you begin to see is that

they follow a faith that features totemism.

Totemism is the belief that people have

a spiritual connection with an animal or a plant.

And that relationship is represented

by a physical totem.

The Hemba use depictions of a primate to honor their dead.

KOUROUNIS: The Hemba revere the monkey.

So it's entirely possible that they would

honor its spirit with a large-scale representation.

But biologists think the strange

spirals may have a different origin.

These shapes look like Fibonacci spirals, and these pop

up in all sorts of unexpected places in nature.

What's more, the Fibonacci spiral can

be expressed as a mathematical formula.

It has been called Nature's secret code.

Nautilus shells are a famous example

of the Fibonacci spiral,

but so are pine cones, sunflowers,

microscopic cancer cells.

NARRATOR: The Fibonacci sequence isn't just found

in the natural world.

Some claim it's also found in the proportions

of some of the world's greatest ancient structures,

from the pyramids of Giza

to the Parthenon in Athens.

Dialing up the magnification reveals a possible clue

to this code's presence in the Congo.

When we take a closer look at this image,

we see that the image is actually not of a forest at all,

and it's actually of a swamp.

So what they could be are fish traps.

KOUROUNIS: If these are fishing traps, that would explain

their Fibonacci spiral shape -- as it turns out,

spirals are a really good way to corral animals

or fish into a small area.

NARRATOR: Fibonacci-shaped fishing traps have

been used for thousands of years.

When fish enter, they encounter a curved wall,

which funnels them deeper into the net.

They keep swimming on, getting further and further into

the spiral, where eventually,

they can't turn around and exit the trap.

To take advantage of that natural pattern and

essentially allow the fish to catch itself --

that's ingenious.

NARRATOR: It's a clever tactic

that's not only employed by humans.

Throughout the world's oceans,

similar spirals suddenly appear on the surface.

KAYS: Humpback whales do a thing called bubble net fishing,

where they swim a quick circle, letting bubbles out of

their blowhole, that creates basically a net that

traps all the fish in the middle.

And then the whales come zooming up with their giant mouths agape

and swallow all the fish.

NARRATOR: Due to the remote location of the strange spirals,

their precise purpose remains unclear,

but they appear to be an unusual example of mankind

mimicking nature.

These spirals certainly look strange from above,

but it's entirely possible that they're a unique

and creative way that these people

have found to help feed themselves.