Original subtitles

NARRATOR: A strange circular island that seems to be spinning.

- That cannot be real. What?

NARRATOR: A giant triangle in the middle of the Arizona desert.

- This is so strange and out of place.

NARRATOR: A seemingly alien landscape

of lurid coloured pools and strange terrain.

- I mean, this is totally bananas.

NARRATOR: And a vast carving

in the middle of the Australian outback.

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?

Looking down from the skies,

our technology can uncover both the every day and the extraordinary.

Amid the predictable and common, we discover seemingly alien landscapes,

freakish phenomenon and traces of unexpected human secrets.

Flying above the Pampas of Argentina,

its cosmopolitan capital, Buenos Aires, stands out on the coast.

But only a few kilometres from the outskirts of the city,

among the ordinary wetlands of the Parana River,

satellites uncover a mystery.

- This is super weird.

- It's a perfectly round island that appears to have been cut

or stamped, as if with the cookie cutter, right into the earth.

- It looks like it's in a really wet, swampy area.

- It's totally bizarre,

and I've never seen anything like this before.

NARRATOR: But it's not simply the perfect shape

that makes this uncanny.

Tracking satellite images through time reveals...

..it moves.

- That is wild.

This round island looks like it's spinning in circles.

- And this isn't small,

it's over 110 metres across.

You could fit a football field on this thing.

- So how is this happening?

What is taking a chunk of land this size and making it spin around?

- Is this a sign of some kind of secret project

or the remnant of a human made feature from the past?

- Or could this be some kind of natural phenomenon?

Is there something hiding underneath the surface that makes this happen?

- There are some ingenious human creations that might be able to help

explain what's happening.

NARRATOR: There may be a clue over 2,000 km to the northwest,

on the border of Bolivia and Peru,

where satellites spot strange shapes floating in Lake Titicaca.

- You can see what appears to be a village out there.

But there's no dry land whatsoever.

- These strange and unexpected islands

are the handiwork of the indigenous Uros people,

and it's where they make their homes.

- There's no sidewalks or streets.

You literally take a boat from one place to another,

or you're walking on these floating reeds.

- And it's truly amazing.

These islands are hand-built by stacking layers of roots

and reeds into giant floating mats.

- The main construction material is the water-resistant totora plant,

which grows in the lake.

- Maintaining the islands is really what I would call a labour of love.

The reeds rot after about 20 days

and need to be replaced with fresh ones.

So it's essentially a never-ending job.

- That's a lot of work.

Why would the Uros keep replenishing these floating islands by hand

instead of just moving to solid ground?

- It's a story that has roots over 500 years ago

in the expansion of the Inca Empire.

- To escape the Inca reaching into their territory,

the Uros built these islands

so that they could be launched far into the lake.

- Really, this was a function of self-preservation.

- Thanks to their ingenuity, the Uros survived.

Today there are around 1,300 Uru people

living on approximately 120 of these constructed islands.

NARRATOR: Could this strange spinning island

be the result of human handiwork?

- Even though it's close to the hustle and bustle of Buenos Aires,

there isn't a sign of human habitation on the island itself.

- And we have satellite images going back about 20 years that don't show

any earlier signs that this was built or used by humans.

- Is it possible for floating islands to occur

without human intervention?

NARRATOR: A clue lies on the other side of the world, in Germany,

where one lake, Kleiner Arbersee, holds something extraordinary.

- There are three islands on this ice-age lake,

but they only appeared around the turn of the 20th century.

And it all had to do with the logging industry.

- Wood was big business in the late 19th century,

and the Bavarian forest around this lake had plenty of timber available.

- The problem was transportation.

All that timber had to be taken over land.

- So, in 1885, the lake was dammed

to make it easy to float that timber down river.

- Once the dam was in place, the water levels rose

and something kind of cool happened.

- Mosses and sedges around the edge of the lake didn't sink,

but broke off in chunks from the subsoil.

And started to float, thanks to their high peat content.

- Under certain conditions, when peat becomes waterlogged,

tiny microbes will start to break down vegetation that is present.

This results in the production of methane,

which gets trapped inside the peat, causing it to become buoyant.

- These turned into floating islands,

about one to three metres thick.

They could even get trees growing on them.

- And just like the spinning island in Argentina,

they could move.

- Because the islands were disconnected from the bottom

of the lake, they would rise and fall with the changing water levels

and move in the wind.

- Nowadays, two of the islands have grown more connected to the lake

and are more stable, but one can still move around.

As weird as this is, it's actually a known natural event.

- The Germans have a great word for it.

They call it, 'schwingrasen',

but in English we just call it a floating mat or a floating bog.

- Floating mats are living communities that grow and change.

Mats of peat moss, which provide a lot of the buoyancy,

are colonised by other plants.

NARRATOR: And these unusual floating islands

have been spotted in marshy areas around the world.

- Is another floating bog

behind the spinning island mystery in Argentina?

NARRATOR: To uncover more,

explorers on the ground in Argentina venture into the wetlands.

- You can see it's almost like a swamp with waist high water

and dense growth of tall grasses.

(in Spanish)

- When they get to the island, what they find is pretty impressive.

(in Spanish)

- And when they stand on the island, they can feel how thin it is.

It's flexible enough to bounce when they jump on it.

They even shove a reed through the ground into the water underneath.

(in Spanish)

- An underwater camera

helps show just how unusual it is under the surface.

You can see roots floating in the water

and then some sort of more interconnected mass.

NARRATOR: Does that mean this spinning island

is like the floating mats in Germany?

- It definitely looks like the same kind of floating island to me,

and that explains what it is, and how it can move around.

- But that doesn't solve the bigger mystery.

- None of these islands, neither the hand-built Uros home,

nor these floating mats

have the same round shape as the island in Argentina.

So what's going on?

- These floating islands of vegetation

make sense in wetlands like this,

but it's still really weird to see one that's so perfectly round.

NARRATOR: A clue could be found in Westbrook, Maine,

where an uncanny event makes headlines in the winter of 2019.

- This is a massive surprise to the people of Westbrook.

A huge circle of ice appearing on the surface of the river.

- Even weirder, you can see in the footage that it's spinning around,

just like in Argentina,

but this looks like it's spinning a lot faster.

- This is big.

Just over 90 metres across,

and it's so unexpected that people nearby rush over to see it.

- How is the ice making this perfect circle and why is it rotating?

- We call these ice disks or ice circles,

and they've been documented all around the planet.

This strange phenomenon is rare, but totally natural,

and happens when the conditions are just right.

- Ice circles form when the edges of waterways begin to freeze.

Currents in the water cause chunks to break off the frozen edges,

and when those chunks get close to one another,

the water between them freezes and they start to stick together.

NARRATOR: But what turns these pieces of ice into precise circles?

- It's the spinning that gives them this round shape.

As the ice grinds against the river bank

or other sections of frozen water, the edges get smoothed out.

It's like sandpaper on rough wood.

- And because it's spinning, this happens on all sides

until it gets shaped into a perfect circle.

- Why it spins is a little trickier.

There's some debate as to whether it's simply a function of wind

and river current.

Others have suggested the temperature differences

between the ice and the water creates this kind of vortex.

- So if ice disks can be made circular from spinning,

could the same thing be happening to this floating bog in Argentina?

- It's a pretty good theory.

It makes sense to think that as the island bumps against the shore,

the edges get eroded away

until the whole thing has a nice circular shape.

- And that same motion probably does the same to the shore;

creating these two perfect circles that form the eye.

NARRATOR: But what invisible force

is making the island spin to begin with?

- Some people think it has to do with a hidden freshwater current,

maybe a spring,

while others think it could be due to wind patterns.

- We can't be certain exactly why this island moves in a circle

like the ice disks,

instead of more randomly like the floating mats in Germany,

but the fact that it is a circle suggests a process of rotation.

- And even though it's clearly a kind of freaky phenomenon,

it's not the only one in Argentina.

NARRATOR: Travelling further up the Parana River,

satellites reveal more of these stunning circular shapes.

- So as bizarre as this seems, it also looks like this could be

part of a mysterious but natural pattern in this area.

We would just never have been able to see it from the ground.

- I never expected floating, rotating, googly-eye islands

to form by themselves anywhere on this planet.

- And we can only ever truly discover and trace

mysteries like these with technology, in the skies.

NARRATOR: Above the rugged terrain of Arizona,

just north of the White Tank Mountains,

Satellites spot something strange

among the ordinary sand, rock, and scrub.

- Looking down from satellite, this desert area,

something really stands out.

A perfect triangle out in the middle of nowhere.

- This is so strange and out of place.

You've got this beige, dry desert on one side

and some roads and houses on the other.

And this obviously isn't part of either.

- It must be human made.

It looks like it might be made out of some kind of concrete or cement.

- And, it's clearly pretty big.

Look how tiny the houses are next to it by comparison.

- It's huge. Each of its sides roughly 1,220 metres long,

and 90 metres thick.

- I mean, obviously this has to be human made, but what the heck is it?

- I'm trying to work out why you would put a triangle

in the middle of a desert.

It's very strange indeed.

- And why does it look like it's been abandoned?

How long has this been left alone out here?

NARRATOR: Can another unexpected abandoned shape provide a hint?

Over 3,000 kilometres to the northeast,

on the south shores of Canada's Georgian Bay,

sits the peaceful holiday town of Wasaga Beach.

- The place is best known

as the home of the largest freshwater beach in the world.

Some 14 kilometres of white sand and clear blue water.

- But just on the outskirts, the nearby forest hides something odd,

and only really clear from the sky.

- The shape looks like the same kind of material as the Desert Triangle,

and just as abandoned. So what happened here?

NARRATOR: To discover the meaning of this road to nowhere,

we have to look into the past.

- Archival records reveal that this neglected structure

used to be a racetrack.

The Wasaga Beach Speedway.

- Built for stock car racing,

this quarter mile track saw some of the most famous racers of their day

make the rounds in the 1950s and '60s.

- Now, what's really interesting is that

while this paved racetrack came to life in the 1950s,

it was actually built in an older half-mile dirt track

used for harness racing.

- Now that's a type of horse racing where the horse is usually pulling

a two-wheeled cart, popular in the 19th and early 20th century.

- The site closed around 1970, and since then,

the surrounding grandstands and structures have disappeared.

- But although there are plenty of cracks in the track,

the oval still stands out, clearly seen from above.

- Is it possible that the massive triangle in Arizona

is another outdated racetrack?

I mean, I haven't seen a corner that tight since Mario Kart.

- There aren't any signs of grandstands or anything,

but perhaps they were torn down like in Wasaga.

- Is there anything nearby that might offer a clue?

NARRATOR: Less than 120 kilometres to the southeast,

another weird Arizona site could be a clue.

Satellites reveal a network of perfectly placed windmill-shapes

made out of triangles.

- There are tons of these odd shapes,

made of a pattern of four triangles

laid out like a windmill or a Maltese cross.

- They cover an almost 26 by 26 kilometre square of Arizona.

- But who would need a perfectly square pattern of crosses

visible from above? And why?

- This pattern is called the Casa Grande Photogrammetric Test Range.

Now, that was used in the 1960s to calibrate equipment

for aerial photography.

- Originally, about 272 or 273 crosses made the pattern,

but maintenance stopped in the early 1970s

and many have been removed or fallen into disrepair.

- But there are still plenty that can be seen from above.

- So could this weird triangle be part of the same secret history?

Is it part of a pattern too?

NARRATOR: Another look from modern satellites reveals

there are more of these unexpected triangle shapes in the area.

- It's clearly part of some kind of pattern.

- But, these don't all look the same.

They point in different directions,

some have additional shapes veering off,

and some have even been partly buried underneath newer buildings.

So, what's going on?

- To figure this out, we need to search for other shapes like this.

So where else can we find giant concrete triangles?

NARRATOR: Across the Atlantic Ocean, in the United Kingdom,

a historic view from above uncovers more shapes that offer a clue.

- Going back in time to the 1940s,

archival aerial images reveal unexpected shapes in the UK.

Shapes that look almost identical to our triangles in Arizona.

- But when we compare the old images with the modern landscape,

we see that many of them have disappeared beneath farmland.

- So what happened?

What were these massive triangles and why did so many disappear?

- The secret lies in World War II

and the very early days of military aviation.

These triangles are actually runways. They're paved roads,

allowing bombers in the Second World War to take to the skies.

(plane whirring)

- In the past, most airfields were just grass landing strips.

But those weren't robust enough for the heavier aircraft

that came along in World War II.

So the British Air Ministry had to develop stronger airfields that were

suited to their wartime needs.

- But you've got to wonder, why are they triangular?

- The design they landed on

is formed of three converging, paved airstrips.

- One runway would be in the direction of the prevailing wind.

That's the safest way to face to take off and land a plane.

And the other strips are in case changing weather makes another

angle a safer and shorter take-off and landing site.

- And because of their shape, they got the name

'Class A' airfields.

- They built so many airfields all across the country that some sources

say that by 1945, the combined length of all these runways was

equal to a 30-foot-wide road from London to Peking.

- So what happened to all these wartime airfields?

- After the war, many of the temporary fields

returned to their original purpose: farmland.

- Now, others were integrated into new commercial airports.

Today, Bristol Airport still boasts a triangle visible from the sky,

which is a reminder that it was once an RAF wartime airfield.

- So are these more relics of World War II?

Did the Royal Air Force pattern make it across the Atlantic?

NARRATOR: The final clue can be found

just over 30 kilometres from the original triangle,

Luke Air Force Base.

- Today, Luke Air Force Base

is known as the largest fighter wing in the US Air Force.

They train hundreds of pilots every year.

NARRATOR: And its history begins in World War II.

- In 1940, President Roosevelt realises the Americans need

a lot of fighter pilots.

So he starts calling for 12,000 per year,

and he eventually increases it to a huge 93,000 every year.

- The Army Air Force springs into action building new airfields,

including on a sizable tract of land in Arizona.

The first trainee pilots arrive in the middle of 1941.

- Luke became the "home of the fighter pilot",

the largest fighter training base in the World War II Army Air Force.

And it successfully trained over 17,000 fighter pilots.

- How are these huge triangles part of the World War II era base?

- Now it's archival maps of Luke Air Force Base

that give us the final piece of the puzzle.

- Every one of the mystery triangles is labelled on this map,

and the map even includes one that's no longer visible.

- That AF on the map stands for Auxiliary Field.

And just like the Class A airfields in the UK,

these are built in a triangle to give pilots options

in case the wind changes.

But why do they need these spare runways away from the main base?

- It's really just a numbers game.

You know, you've got thousands of World War II pilots to train,

and Luke Air Force Base therefore needs a lot of runway.

- This way, pilots could take off from the main base

where the barracks and things are,

and then spread out to these auxiliary fields.

- So it's there that pilots would practise various types

of approaches, take-offs, landings.

So all these auxiliary airfields were a really handy way to maximise

the number of manoeuvres, and of course airtime.

- And these fields could also serve as emergency landing sites

or refuelling stops for other aircraft.

- But, if they were so important, why were they abandoned?

NARRATOR: With the end of the war, fewer pilots go through training

and fighter aircraft technology continues to advance.

- Just like the changes between the First World War

and the Second World War

that made the new Class A fields necessary in the UK,

today's military aircraft need longer runways

and they need stronger runways.

(whooshing)

- Most of the auxiliary fields returned to civil authorities.

One became Buckeye Municipal Airport.

- Most of the others have been left to be reclaimed by the desert

or disappear under more modern construction.

- But one of them

is actually still used by the pilots of Luke Air Force Base today.

That's Auxiliary Field 1.

Even if the runways are too short or two weak, pilots can still practise

different types of approaches that don't require an actual touchdown.

- And the triangles are still clear landmarks from above,

marking the long history of the Air Force in the Arizona skies.

NARRATOR: Desert sands hold unexpected and shocking secrets.

A view above the northern border of Ethiopia

reveals cracked desert for as far as they eye can see.

When suddenly, everything changes!

- Wow.

- This is utterly alien.

- Is this another planet? What am I looking at here?

- There's pretty much every colour of the rainbow here.

Oranges, yellows, browns, these bright greens, almost neon.

- This is not what you'd expect to see

in the middle of some vast brown desert.

What is that?

- How did these get here?

Where are all these colours coming from?

- What I want know is, is this place dangerous?

It looks like a very kind of toxic place to have a swim.

NARRATOR: This hypnotising landscape is known as the Dallol Pools.

And it has an intimidating reputation.

- It's been called the Land of Death.

- And it's no wonder, year round this place is stifling.

- It's one of the hottest places on Earth with the highest average

year-round temperature of any inhabited place on our planet.

- In the summer, it can regularly get above 50 degrees Celsius.

NARRATOR: But there are signs of human activity nearby,.

Within walking distance of the pools, where a view from above

reveals a haunting site that could hold a clue.

- Well that looks kind of creepy.

- What is this place?

And what happened?

- This place is totally abandoned.

The roofs are gone, the walls are crumbling, you know, it's a mess.

It's a ghost town in the middle of a desert.

- Who built this place?

And where did they go?

NARRATOR: These are the ruins of an old mining camp.

- It all started in the early 1900's when two brothers from Italy

came to Ethiopia in search of adventure and treasure.

- They absolutely hit the jackpot

when they discovered that the earth around Dallol was rich in potash,

which is used to manufacture fertiliser and explosives.

(explosion booms)

- A few years after the brothers discovered potash in Dallol,

the First World War broke out and demands skyrocketed.

It was a lucrative operation. So, what happened?

- When the war ended, buyers dried up and the camp was abandoned,

but not for long.

NARRATOR: About 30 years later

an American mining company came to Dallol.

- The Americans moved into the old Italian camp

and did a little renovating.

- You can see the more modern white structures.

Now, those were built by the Americans

versus the original earthen bricks used by the Italians.

- But there was this really deadly flood

in one of the mineshafts in 1967,

and it killed several workers.

Of course, work stopped but also there was a lot of political tension

in the region, and that kept other companies away.

- The mining camp become a ghost town once again.

NARRATOR: Today, it's a decrepit, rusting scar in the desert...

..but could this 20th century mining operation explain this mystery?

- Can mining operations cause anything that looks like this

weird landscape in Dallol?

NARRATOR: The view from above around the world

uncovers a range of lurid rainbow hued waters near known mining sites.

- Colours can range from bright teal, to orange, to green.

- But what's making this weird rainbow of colours?

NARRATOR: In some cases, it's deliberate.

- In Utah, blue dye is added to salty brine pools.

- The dye speeds up the evaporation process, eliminating the water

and leaving behind the salt for extraction.

NARRATOR: But in other cases,

these bold colours appear after a mine has been abandoned.

- And the secret behind this process is hidden underground.

- In open pit mines digging often goes well below the water table,

which means it's really susceptible to water coming in.

- As natural groundwater seeps in, it's pumped back out.

But, when the mine ceases to operate, the pumps are removed

or turned off.

That means that the pit can flood

and minerals will leach into the water through the exposed rock cuts.

- This now polluted and contaminated water can turn all sorts of colours.

- Water can change colour drastically

depending on what's been dissolved in it.

- Teal shades can come from chlorides

or you can get shades of blue from dissolved limestone.

Iron oxides turn things bright orange or red.

And while it looks like a happy rainbow of fun,

you do not want to swim here.

It's actually very dangerous.

- When minerals and metals leach into water,

it can become highly acidic and toxic.

NARRATOR: Are the brightly coloured pools at Dallol

abandoned mining pits, filled with toxic water?

- Dallol's pools are less than 300 metres

from the abandoned mining camp.

- But according to historical records,

neither the Italians nor the Americans mined near the pools.

- So if these pools aren't the result of human mining operations,

how on earth did they form?

- Where is the water coming from? And why is it so brightly coloured?

NARRATOR: A view from above the pools

may offer some smoking gun evidence.

- The pools of Dallol are surrounded by steaming earth,

and the water inside them is bubbling.

- So what's causing this landscape to spew and smoulder?

NARRATOR: There may be a clue just 80 kilometres away.

This is Erta Ale, Ethiopia's most active volcano.

- Erta Ale is pretty special.

It's one of the few volcanoes in the world with an active lava lake.

- Lava lakes are situated inside volcanic craters

and contain a massive amount of molten lava.

- Lava lakes are one of the rarest natural phenomena on Earth.

At any given time,

there's maybe only half a dozen of them that are active.

And they're kind of like a window into the centre of the Earth.

- In most cases, lava lakes appear and then solidify quickly.

But the one at Erta Ale has been persistently active

ever since it was first discovered in 1906.

That makes it the world's longest known lava lake.

- To see one of these things with your own eyes, it is amazing.

I travelled to this remote volcano back in 2005.

When I finally got to the volcano,

it was 100% different from what I was expecting.

Typically, Erta Ale boils and churns away

with this lake of liquid rock, this lava lake.

And if you're to stand at the edge,

the heat would be absolutely unbearable.

But unexpectedly, the level of the lava had risen up,

overflowed a ledge that I had planned to descend down to,

and then a crust formed on top.

There were a few features on the surface of the lava lake,

these hornitos, these small cones that come up,

and we could see lava sputtering and spurting out of these cones.

So we knew the volcano was still really active,

but it was extremely unpredictable.

Once we determined that it was strong enough for me to walk on,

I was able to repel down

and step where no human had ever set foot before.

And as I was walking across,

the ground actually gave out beneath me and I dropped,

not knowing if I was going to plunge into this lava,

and the team was gonna pull up a rope with just a scorched end on it.

Luckily, I only dropped down about a foot or so,

but let me tell you, my heart was pounding.

So I knew I should probably limit my time down there.

I scrambled over to the side of the hornito,

broke off a few lava samples, and then got out of there.

Let me tell you, it was an exhilarating experience that

I don't think I'm in any rush to recreate anytime soon.

12 people have been on the surface of the moon,

only one person has walked on the crust of that lava lake.

- Could there be some kind of connection between the lava lake

and the eerie waters of the Dallol Pools?

NARRATOR: The final clue is hiding beneath the ordinary desert sands.

Erta Ale, and the Dallol Pools, are part of something much much bigger.

- Both Erta Ale and the Dallol Pools sit in a place

known as the Afar Triangle, aka, the Afar Depression.

- The Afar Triangle is a spot where three tectonic plates meet,

and are currently pulling apart.

Scientists are pretty sure that eventually, Africa will split in two

and water from the Red Sea will rush in burying parts of the landscape

and creating a new ocean.

- But this isn't exactly a fast process.

NARRATOR: Scientists predict that this will happen in millions,

or even hundreds of millions of years from now.

- But in the meantime?

This activity puts a lot of stress on a lot of rock.

That results in all kinds of geologic and geothermal activity

including volcanoes.

NARRATOR: But what does that mean for the Dallol Pools?

What are these planet shaking forces hiding below the surface?

- It seems unbelievable but Dallol is a volcano too!

- It definitely doesn't look like your classic science-fair volcano.

(eruption booms)

- When most people think of a volcano,

they picture a tall cone looming over the landscape.

NARRATOR: Dallol rises just 60 metres

above the surrounding salt plain,

but a view from above reveals the tell-tale shape of a volcanic mound.

- In the last 100 years,

Dallol has experienced at least two sizable events.

But even when it's not exploding,

there's enough geological activity to fuel this wild landscape.

NARRATOR: The interaction of water and magma below the surface creates

the steaming earth and bubbling pools.

- These pockets of water are hot springs,

super heated by magma below the surface.

- They can hit temperatures of 112 degrees Celsius,

and they are super acidic.

- This is totally the kind of place that a James Bond villain would use.

If a human were to fall in, they would die. No question.

- These pools are rich in minerals, chemicals and gases,

and that's what gives them their intense colouration.

- The crust around the pools is made up of salts and sulphur.

As those elements get exposed to extreme heat and air,

they can change from white and yellow

to deep shades of red and brown.

- A volcano on its own, is pretty damn awesome.

A volcano with its own hyper colour hot springs?

That's next level.

NARRATOR: The Australian Outback

is known for its incredible natural rock formations

and its endless red sands.

- The Australian Outback is famous

for being this vast expanse of desolate nothingness.

There's very little out there other than sand dunes, kangaroos, spiders,

and snakes.

(snake hisses)

NARRATOR: But among the rugged and extreme terrain,

near the small town of Marree,

the view from above reveals something totally unexpected.

- We see what looks like an open desert mountainous area,

but in the middle there's a shape.

- It looks like an anthropomorphic image has been cut into the earth

and it's holding something in its hand.

- It's a massive nude man.

- This geoglyph is really big

spanning around 3.5 kilometres

- And that's all the more dramatic,

because there's simply nothing else around it.

- This is wild.

What is this huge carving doing in the middle of nowhere?

- Locals call this the Marree Man, but who is this mystery figure?

- Is this a relic of an ancient civilisation

leaving their mark on the landscape?

- I'm trying to work out what he's meant to be.

I mean is this a warrior or a hunter or maybe he's some kind of god?

- There is something familiar about the shape

and pose of this huge figure.

NARRATOR: Perhaps a clue could lie

on the other side of the world, in Greece,

with an ancient treasure discovered in the Aegean Sea.

- This is what's known as the Artemision Bronze.

It's a two-meter-tall statue,

likely dating back to around 450 or 460 BCE.

What's special about a lot of Greek art is the choice of the pose.

The Artemision Bronze is in a pose that is very common for depictions

of Zeus, king of the Greek gods.

- Usually Zeus is depicted in the act of throwing a lightning bolt,

but whatever the Artemision Bronze was holding

has been lost through time.

- What's really weird is that this ancient statue is a mirror image

of that human shape in the Australian desert.

So, is it possible that these two images are connected in some way?

- But what would a Greek god

be doing in the middle of the Australian Outback?

NARRATOR: Why would these two forms,

separated by thousands of kilometres look so similar?

- Ancient Greeks did explore a lot of their world by sea,

but its pretty unlikely they made it all the way to Australia,

let alone the Outback.

- And there's a big difference between a two-metre statue

and a geoglyph over two kilometres long.

- Can other ancient earth markings offer a clue?

NARRATOR: On the other side of the Pacific, in California,

more human figures have been etched into the sands.

- This is part of what's known as the Blythe Intaglios,

a group of six geoglyphs that include human shapes.

Their age is uncertain

but estimated to be somewhere between 450 to 2,000 years old.

- These aren't quite as big as the carving in Australia.

The largest is about 52 metres high.

- But you've still got to wonder who could be

so important that they inspired these massive depictions?

- Local Mojave people say these are representations

of their people's creator, Mastamho,

and other figures from their traditional stories.

- Some sources suggest

these geoglyphs served a religious purpose,

invoking the gods for protection,

and perhaps as sites for sacred dances.

NARRATOR: Is the lonely human form in the Australian Outback

another ancient geoglyph?

- Could this have been created for spiritual purposes

by the indigenous peoples of Australia?

- Australia does have some famed ancient art

at one of the most important rock art sites in the world.

NARRATOR: Far to the northeast of the Marree Man,

in the remote wilderness of Queensland,

on the Cape York Peninsula.

- Spread across a huge area,

sandstone caves and rock outcroppings

form the canvas for images from the long distant past.

- Now, these stunning drawings are thought to be incredibly old,

from around 15,000 to 30 or even 40,000 years ago.

- The art in this region is famed

for its impressive breadth of images,

encompassing a range of eras, types of images,

and maintaining an impressive quality despite their age.

- The Aboriginal people who lived here and made this art,

really this record of their life,

represents the longest continuous art and culture that we know of.

- So is it possible that the Marree Man

is part of this long history of Aboriginal rock art?

- It makes sense.

I mean, if you look closely at the Marree Man,

it could be holding a traditional Aboriginal boomerang

or throwing stick.

- But there's another really crucial clue found in the view from above,

and it completely upends all our expectations.

NARRATOR: A look back in time from above reveals something staggering.

- The Marree Man was first spotted from the air

by a pilot in June of 1998.

They probably thought they had uncovered

some major ancient geoglyph.

- When we look at those past satellite images,

we can only start to spot the Marree Man

from June of 1998.

NARRATOR: In that image, the figure is clearly visible,

but only a month earlier, there's nothing but desert rock.

- So the pilot who discovered it from above must have spotted it

just after its creation.

- As unbelievable as it seems, this is modern.

But who made this, and why?

- And how is it possible that something this huge could be

created in the desert without anybody knowing?

NARRATOR: With the vast history of Aboriginal art,

some might wonder if this is part of their tradition.

But news reports at the time reveal the local Aboriginal peoples

were not impressed by this incursion on their land.

- They're outraged and they're disgusted by it,

and I think every time the issue comes up again,

similar feelings echo throughout our community.

NARRATOR: So who is behind this vast and extraordinary figure?

A trail of strange clues emerges.

- At the time of its discovery in 1998,

anonymous faxes were sent to local news outlets

offering tantalising hints and clues to the provenance of the geoglyph.

- These clues suggest the Marree Man could be a clandestine project

by members of the American military stationed in Australia.

- That kind of makes sense.

An organised team with military equipment available

seems like enough to complete such a large project.

But why would they do it?

- It's possible that all these clues were red herrings

and the real person, or people, behind it,

were just trying to cover the trail.

- Some think that the most likely culprit

was a local artist in the nearby town of Marree

determined to make a sizable mark and have a little bit of fun.

- Could this person simply have used early GPS technology

and heavy machinery alone to draw such a massive figure undetected?

NARRATOR: Can a recent project at the Marree Man

offer a hint to its creation?

Since its appearance in 1998,

the winds and weather of the desert began to wear away the geoglyph.

- Eager to keep the tourist-friendly landmark in place,

in 2016, a team equipped with major machinery

freshened up the geoglyph to ensure it remains visible from above.

- And it was no easy task.

The difficulty of the refresh, 18 years after its original appearance,

hammers home how tricky its creation must have been in the first place.

- GPS wasn't as ubiquitous as it is today,

and the US was scrambling satellite signals

to deliberately reduce GPS accuracy until the year 2000.

- Now, that restoration used some seriously heavy equipment, you know,

a big grader to redraw those lines.

So how can someone be doing that completely in secret?

How did they even get whatever they used right out there?

I mean, it's mad when you think about it.

NARRATOR: The mystery behind its creation remains.

- As of yet, no one has come forward

to claim the creation of the Marree Man.

- It seems totally bananas to me,

that someone would create something this impressive, this huge,

something designed to be seen, you know,

by planes and satellites, and not want to take the credit.

I mean, I would tell everybody if I made it...

- Perhaps one day the view from above will uncover the truth.

NARRATOR: Major human projects or eerie natural phenomena,

eyes in the sky searching above ordinary landscapes

uncover the uncanny and unexpected in the most unlikely places.

Subtitles by Sky Access Services