NARRATOR: They're watching you.
More than 6,000 satellites circle the Earth.
Every day, they uncover new, mysterious phenomena
that defy explanation.
The mystery of the exploding island.
[explosion blasts]
The energy released could create
the biggest tsunami humanity has ever seen.
NARRATOR: America's lost mega structure.
It was considered by many to be
the Eighth Wonder of the World.
NARRATOR: And Stalin's hell ships.
RODRIGUEZ McROBBIE: You could only pray that you would make
it out alive or die as quickly as possible.
NARRATOR: Baffling phenomena, mysteries from space.
What on Earth are they?
[theme music playing]
October 1st, 2021.
As NASA's Aqua satellite orbits more
than 400 miles above the Spanish island of La Palma,
it captures this image.
This island in the eastern Atlantic had
something weird going on with its weather.
LEE: We're seeing a concentric series of
bright rings, which is really very mysterious.
NARRATOR: The weird rings are between 5
and 30 miles in diameter.
This is a highly unusual pattern to see in the clouds.
A. MORGAN: It looks like an enormous
bullseye completely obscuring the island.
NARRATOR: Satellites have captured strange phenomena
in our skies before,
freak patterns caused by meteorological
disturbances in the upper atmosphere.
But image analyst Ken Joyce believes
what he's looking at is unique.
I'm gonna take a look at this island
and see what might be going on.
NARRATOR: Joyce uses historic images to scan through time.
One taken shortly after the mystery event
draws his attention.
As I bring that image into view,
it's absolutely shocking what I see.
There is graphic volcanic eruption happening right here.
I can also see that the center of
the bullseye is right over where the eruption is occurring.
NARRATOR: Further aerial imagery confirms that La Palma is
in the grip of an unfolding natural disaster,
Cumbre Vieja,
a 6,400-foot-high volcanic ridge,
has awoken from its 50-year slumber.
On September 19th of 2021,
the volcano spews out jets of ash and lava,
while rivers of molten rock pour downhill,
destroying absolutely everything that it touches.
As it erupts, Cumbre Vieja
unleashes rivers of lava three stories high,
which relentlessly engulf communities below,
swallowing 3,000 homes.
A. MORGAN: The islanders are scrambling as fast as they can,
because they know that anything
that the lava touches does not stand a chance.
All the residents can do is sit and watch in horror
as their livelihoods are destroyed by this relentless
river of molten rock.
NARRATOR: Just how the volcano created
the weird rings remains unclear.
To investigate the devastating eruption,
a team of U.S. scientists has come
to La Palma to study the disaster up close.
Nothing could prepare us for the sight
we were about to see.
We come around this corner, and there is
a red column of lava right in front of us.
NARRATOR: The team discovers a ruined landscape encased
in lava fields over 200 feet thick.
All I could think about was
how nightmare-inducing this landscape is.
I'd never seen destruction like this in my entire life.
NARRATOR: Such is the destructive power
of volcanoes that their inner workings
are largely a mystery to scientists.
To decipher the one revealed from space,
the team is turning to the latest in aerial technology.
We are bringing drones to the island, because drones are
the perfect vehicle to collect data from the erupting volcano.
RUBEN: Drones can fly right into the active volcano,
capture samples, and bring them right back
to the scientific team.
NARRATOR: Volcanic eruptions are fueled by a mix
of gases found in the magma chamber.
By studying the composition of these gases,
scientists can work out how deep the chamber
is and how long the eruption could last.
If the magma chamber is shallow,
that means it could empty quickly,
and the eruption will be short.
But if the chamber is deep, then the eruption
could be long and intense,
which would be bad news for the people of La Palma.
NARRATOR: Each of the drones is fitted with a device,
which can collect gas samples from the center of the plume.
By making repeated passes over the volcano,
the scientists begin to build up
a picture of what lies beneath.
The data confirms their fears.
Correlating our samples, we're able
to determine how violent the eruption is.
Our results show that, unfortunately, the magma
came from a very deep source, and there was a lot of it.
NARRATOR: The drone data reveals that
Cumbre Vieja's infernos are being fed
by a giant magma chamber some 40 miles beneath the island.
RUBEN: That is a ridiculously deep chamber,
and it may help explain why
the eruption of this volcano was so violent,
intense, and long-lasting.
This tells us that the eruption
could continue on for quite some time.
NARRATOR: Studies of Cumbre Vieja's plume also
explain the strange rings in the image.
What we have going on is an extremely rare
and unusual combination
of different atmospheric phenomena at the same place
at the same time.
NARRATOR: In the hours leading up to the rings forming, a front
of warm air from the Sahara desert sweeps over the volcano.
When the rising plume of gases hits this warmer
desert air, it acts like a lid, trapping it.
It has nowhere to go but outwards, and as the volcano
explosion pulses over and over again throughout the day,
you get these rings that form in the atmosphere.
Basically, the volcano is burping.
It's putting out one blast of air, and that forms a ring,
and then another blast of air forms another ring.
That's, in essence, what this volcano was doing.
NARRATOR: As Cumbre Vieja continues to vent its fury,
it fuels concerns that it could wreak devastation well
beyond the shore's of La Palma,
devastation that would claim millions of lives.
Unfortunately, this has the potential to be a deadly
situation for anybody in the Atlantic along the coast.
If the volcano collapses, the energy released
could create the biggest tsunami humanity has ever seen.
NARRATOR: Coming up,
the 500-billion-ton time bomb.
All we can do is hope this is the last we'll see
from this volcano in our lifetimes.
NARRATOR: And the island of the disappeared.
Something bad happened to produce this vacuum.
NARRATOR: Strangely-shaped clouds captured from space
have alerted analysts to
a cataclysmic volcanic eruption on La Palma
in the Canary Islands.
Those concentric circles are the results
of the volcano erupting in bursts.
So each ring is one of those bursts.
NARRATOR: Thousands of lives are at risk.
But some fear much worse is to come.
Some researchers have suggested that La Palma Island
could potentially be a ticking time bomb,
a mega disaster the likes of which
we have never seen before.
NARRATOR: The fuse for this time bomb is lit
around four million years ago when
La Palma and the other Canary Islands begin to rise from
the sea floor.
As the land masses form,
vast amounts of magma are also forced upwards.
DENNIE: The Canary Islands are what's called a hot spot,
the place where deep down in the mantle of the Earth,
we've got hot rock rising up until it erupts at the surface.
NARRATOR: On La Palma,
over countless millennia, these eruptions create
a nine-mile-long volcanic spine
running north to south across the island.
Seven decades ago, it begins to disintegrate.
In 1949, an eruption takes place at a Cumbre Vieja,
which opened a giant gash along the volcanic ridge.
This created a split along the top of the volcano.
NARRATOR: The giant crack also causes the western half
of the ridge to slip by several feet.
The nightmare scenario is that the eruption revealed from
space could finish the job begun back in '49.
The fear is that if enough gas builds up,
and there's a big enough eruption,
it could crack the volcano in two.
If that were to happen, it would create a mega tsunami
much larger than anything that we have seen in modern times.
NARRATOR: The largest recorded mega tsunami
takes place in 1958,
when a 1,700-foot-high wave sweeps across
Lituya Bay, Alaska.
It is generated by 90 million tons of falling rock.
The La Palma eruption could unleash
more than 5,000 times that amount.
Volcanic activity along this ridge could result in
a giant piece of the island just sliding into the ocean.
RUBEN: All that rock would displace the water,
creating enormous waves that would travel out in
all directions.
NARRATOR: As the massive rockfall slams into the ocean,
scientists believe it would generate a surge of water over
3,000 feet high.
A series of giant waves would then spread across
the Atlantic at speeds of up to 500 miles per hour.
The most devastating tsunamis in recent history
happened as a result of underwater earthquakes,
but the collapse of a volcano into
the ocean could unleash even greater destruction.
NARRATOR: The mega wave would engulf coastal areas of Europe
and the U.K.,
and the destruction it wreaks in
the Americas could be even greater.
This wave would travel at near supersonic speeds, completely
overtaking all the Caribbean islands
and impacting the highly densely populated
areas of the U.S. east coast.
When you consider just how populated
some of these coastal cities are,
it's easy to see how they could feel
extremely vulnerable.
NARRATOR: The mega tsunami could sweep up to 20 miles inland from
Boston to Miami,
destroying entire cities and killing millions.
And while some dismiss such a scenario,
there is evidence that it has happened before.
In the Bahamas, researchers have found giant
displaced boulders that suggest
these types of ocean-crossing tsunamis
might have happened in the past.
So who's to say it couldn't happen again?
NARRATOR: On December 25th, 2021,
Cumbre Vieja finally falls silent.
The danger posed by the mega tsunami recedes,
but the volcano could soon erupt again,
meaning the threat is far from over.
All we can do is hope this is
the last activity we'll see from this volcano in
our lifetimes.
NARRATOR: Coming up, destroyed in seconds.
It just goes to show that no matter the heights of
human ambition,
everything can come crashing down.
NARRATOR: And the building blocks of life.
These contain the clues to the birth of the universe.
NARRATOR: September 27th, 2019.
A satellite scans dense forest
in the northeastern United States.
Here we are, deep in the woods of Pennsylvania,
and we're seeing something quite unusual.
In this clearing,
you can see what appear to be studs sunk into the earth.
A. MORGAN: And then next to that are these triangular-shaped,
almost like ladder structures that have been tipped over.
I don't know what this is.
NARRATOR: The mystery shapes sit in an isolated 20-acre clearing.
AUERBACH: The clues to this structure
might lie in our location.
We're in a heavily forested area,
and if we roll back to the 19th century,
the timber industry was really booming in this region.
I'm wondering if we're looking at the remains of
a very clever 19th century technology that revolutionized
the logging industry -- the log flume.
NARRATOR: From the middle of the 19th century,
U.S. lumberjacks clear an area more than five times
the size of Florida
in the space of just 60 years.
RODRIGUEZ McROBBIE: As timber supplies depleted,
loggers had to move further and further inland
to meet the demand.
This necessitated new methods of transportation.
NARRATOR: In 1868, a Nevada lumberjack
develops the log flume.
Soon these chutes are ferrying logs up to 60 miles to mills,
which churn out enough timber to fill nearly 5,000 modern
logging trucks per year.
RODRIGUEZ McROBBIE: You didn't need to build expensive roads,
you didn't need to have oxen pulling carts full of wood.
All you needed was gravity.
NARRATOR: It turns out that the structure does have
its origins in the 19th century,
but it's a legacy of a very different industry.
This is an extraordinary relic of America's journey
to become the greatest and most powerful
of all industrial nations in the world.
NARRATOR: Between 1865 and 1900, America's economy explodes,
transforming a nation ravaged by civil war
into the world leader in manufacturing.
This so-called Second Industrial Revolution is built on iron
and steel, but powered by coal.
Industries are expanding at a phenomenal rate,
and America's hunger for fuel is insatiable.
Coal was indispensable to the rise of the nation.
Coal was king.
NARRATOR: The country's biggest consumer of coal is New York,
which handles more people and cargo
than all other American ports combined.
It needed coal to heat its homes, to run its factories,
to run the ships that come in and out of New York harbor.
But the coal was located several
hundred miles away in western Pennsylvania.
NARRATOR: In the 1880s, engineers decide to build
a new rail line connecting New York
to the coal mines of Pennsylvania.
But there's a problem in their path --
a 300-foot-deep ravine called the Kinzua Creek Gorge.
The railroad owners faced a choice -- either lay down
eight miles of new track or find some way over the gorge.
AUERBACH: In the true spirit of
the American Industrial Revolution,
they chose the most radical solution.
They chose to go directly across this massive gorge.
NARRATOR: On May 10th, 1882,
engineers begin work on a revolutionary viaduct
using 1,400 tons of preassembled
wrought iron pieces.
To get the first enormous tower up,
they had to use something called a gin pole,
basically a big tower, and they would use that to erect
the next one and that to erect
the next one, kind of like reverse dominoes.
NARRATOR: Using this method, it takes 40 people just
94 days to construct the world's tallest
railroad bridge.
This means that the biggest towers in the world at
that time were built in just a matter of months.
HUNT: This was such a feat,
it was considered by many to be the Eighth Wonder of
the World, and people would come from miles to look at it.
NARRATOR: Such is the bridge's popularity
that when it opens, a passenger service is added
to the freight line.
CERVENY: Riding across this gorge on the railway
would have been an experience unlike anything else.
This would have been an equivalent of flying
in an airplane before there was an airplane.
NARRATOR: However, the bridge's success is short-lived.
Advances in technology mean that within
20 years, rail engines become 85 percent heavier,
and the structure becomes unsafe.
So in 1900, it had to be entirely rebuilt, this time
in steel instead of the original iron
to hold these heavier trains.
NARRATOR: Freight services over the gorge
finally end in 1963,
but it's an event 40 years later that
creates the trail of destruction visible in the image.
The real end to the Kinzua Bridge
comes when Mother Nature steps in.
A tornado with peak winds of 100 miles an hour hit the side
of the bridge, and within seconds,
the whole thing basically crumbled to the ground.
NARRATOR: Today, the Eighth Wonder of the World
is a tombstone to a bygone era,
when humankind's ambition seemed limitless.
It just goes to show that no matter the heights of
human ambition,
it can take one moment, and everything can come
crashing down.
NARRATOR: Coming up, World War I's Alcatraz.
RODRIGUEZ McROBBIE: This was the setting for some of
the most harrowing operations of the First World War.
NARRATOR: And the Scottish sea monster.
It has this appearance of
a comet that's headed straight for you.
NARRATOR: July 2nd, 2021.
A satellite orbiting above the country of Azerbaijan
scans an arid landmass three miles from the coast.
This is a desolate island.
There are roads crisscrossing it,
some structures here and there,
but it looks like it's been abandoned for some time.
M. MORGAN: Whenever you have a place where humans have just
walked away,
there's always a bit of an eerie feel to it, like
something bad happened to produce this sudden vacuum.
NARRATOR: A boneyard of rusting ships sits nearby.
There are vessels tied up to docks,
which look like they're half sunk.
It's kind of a creepy picture here.
NARRATOR: Analysts turn to local records.
They reveal the ghost island is the legacy of a series
of brutal, bloody events that begin more than a century ago.
What these reports tell us is that this area
was the setting for some of the most harrowing
non-combat operations of the First World War.
NARRATOR: In October 1914,
Turkey's Ottoman Empire enters World War I,
siding with the German Empire.
While Germany focuses on capturing Western Europe,
Ottoman forces attempt to
secure countries around the Caspian Sea,
including Azerbaijan.
Turkey joins the war on the side of Germany, because
she sees this fantastic opportunity to seize
all this new territory, but there's a problem.
That means going up against its historic rival, Russia.
NARRATOR: The better equipped Russians
devastate the Ottoman Army,
slaughtering 23,000 and capturing a further 7,000 as
prisoners of war.
Russia, who is fielding a massive army,
is fighting against a rather we weak Ottoman army on
the other side, and the result is
thousands of Ottoman prisoners that all have to be dealt with,
somehow, somewhere.
WALTERS: To buy themselves some time,
they send all the surplus prisoners to this desolate
rock on the Caspian Sea,
and that is known as the Isle of Nargin.
NARRATOR: Surrounded by miles of sea,
the island becomes a kind of World War I Alcatraz
for thousands of wounded and disease-ridden prisoners.
Imprisoned in the filthy barracks
in the image, countless starved to death.
The island is alive with snakes.
The men are forced to eat the snakes,
because they're not receiving nourishment
from their Russian captors.
If you were sent to an Nargin,
you could only pray that you would make it out alive, or that
you would die as quickly as possible.
NARRATOR: In September 1918, Turkish forces
liberate the island's surviving inmates.
The following decade,
it and the rest of Azerbaijan are captured
by the Soviet Union,
and the horrors witnessed here enter a new chapter.
The island eventually evolved into
one of the Soviet Union's prisons.
It's where Stalin would send perceived
enemies of the state or political prisoners.
NARRATOR: Between 1936 and 1938, Stalin launches a ruthless
campaign to solidify his power,
known as the Great Terror.
Over one million people are imprisoned
and 750,000 more murdered by the state.
Of all the Gulags to be sent to during the Great Terror,
Nargin Island was probably the worst.
It essentially was a place to be sent
to if you were going to be executed.
NARRATOR: Stalin uses Nargin Island to execute both
high-ranking officials and thousands of ordinary citizens.
As his paranoia increases,
so do the horrors inflicted on the prisoners there.
At the height of the Great Terror,
the state actually surpassed the idea of just executing
political prisoners
to transitioning to full-scale extermination of these people.
CAVELL: D isposing of the vast numbers of people that
this regime was looking to get rid of,
that becomes an expensive prospect.
And so there are attempts to try
and eliminate the problem as cheaply
and efficiently as possible.
NARRATOR: During the Great Terror,
around 1,000 executions take place every day,
and mass killings are commonplace.
This gives rise to harrowing rumors as to
the purpose of the ghostly vessels seen in the image.
Some reports actually suggest that the ships that are sunk in
this harbor may have
contained thousands upon thousands of victims who were
purposefully sunk in the bowels of the vessels.
NARRATOR: Soviet authorities eventually abandon the island.
But even today, life has yet to return to this place of death.
Although we will never know the number
of people who perished on this island,
it is nevertheless forever haunted by the legacy of
the conflict and the extremist political ideologies of
the 20th century.
NARRATOR: Coming up, time travel in the mountains.
This looks like a lair for a Bond villain.
NARRATOR: And a monster rises from the depths.
You have this tail that's pushing
its way back out towards the sea.
NARRATOR: March 9th, 2020.
A satellite flying over southern Japan spots
a bizarre shape in the mountains below.
MUNOZ: We're looking down on this remote,
dense forest, and within the trees is this weird
geometric structure.
CAVELL: It's a very distinct pattern with adjacent buildings.
I mean, this looks like something of
a mountain lair for a Bond villain.
NARRATOR: The mystery structure is over 400 feet wide.
Analysis suggests it could indeed serve
a nefarious purpose.
WALTERS: If you look closely, you've got these six
lines coming from these small structures towards the center.
CAVELL: The first question I have,
is there a hatch here, is this some kind of missile silo?
It looks like something military.
NARRATOR: Japan's post World War II constitution
allows the country to maintain self defense forces
but prohibits it from engaging in conflicts
with foreign powers.
Today, escalating tensions in
the region are testing the country's resolve.
Japan's primary threat is North Korea.
Now, that is an unpredictable and volatile enemy,
and they threatened Japan for decades.
MUNOZ: North Korea has developed weapons
that can strike targets inside Japan.
NARRATOR: In response, Japan has pledged to double
its military spending to over $100 billion dollars
and is upgrading its missile systems.
CAVELL: Japan is looking to defend itself by investing
in deterrent type weapons
that can shoot down a potential incoming warhead.
WALTERS: Japan's a small, densely populated country.
But the location in this satellite image is a long
way away from major populations
so it could be a perfect spot for a silo.
NARRATOR: However, local government records reveal
the facility has a very different function.
As we look closer at the surface of this structure,
we can see that there is a fast array of small antennas
on all these individual cells.
What we're looking at here is the MU array.
M stands for middle atmosphere.
U stands for upper atmosphere.
It's an atmospheric observatory.
NARRATOR: Our planet's upper and middle atmospheres sit
between 5 and 6,200 miles above the Earth's surface.
They shield us from solar radiation
and destroy meteors
and asteroids before they endanger humanity.
But despite the critical role each plays in our lives,
they remain poorly understood by scientists.
The Earth's middle and upper atmosphere is one
of those areas that just hasn't been explored.
OKEREKE: Just like we know very little
about the deep ocean or deep space,
there are areas of our atmosphere that we look up to
every day that we know very little about.
NARRATOR: The MU array uses 474 separate antenna to gather data
on the composition and role of our planet's different
atmospheric layers.
It helps predict and decode extreme weather events,
such as the typhoons, which regularly devastate this region.
But that's just the start of its capabilities.
So the MU array is actually detecting cosmic
dust in the middle and upper atmosphere.
Cosmic dust is material that has
been ejected from collisions out in space.
CAVELL: The reason we study these tiny particles of dust
more than 180 miles above the Earth's surface
is that these particles actually
contain the clues to the birth of the universe.
NARRATOR: Cosmic dust particles are
the building blocks of celestial objects.
When these objects disintegrate or explode,
the dust released can form giant clouds,
which then create new stars or planets.
LEE: This dust is really a priceless source
of information.
It's pristine material from the earliest
times of the formation of our planet.
Some of these little tiny specks of dust are more than
4.5 billion years old,
and it gives us a clue into what the galaxy is
actually made of.
NARRATOR: On Earth, billions of years of tectonic upheaval
and movement in our planet's molten core
has erased all evidence of its original makeup.
Working with another telescope,
scientists at the MU array can turn back time to
work out where our planet and everything on it came from.
So a normal radar fires out a pulse that hits off of
a large object, and it receives that pulse back,
and it measures that distance.
These objects are too small.
So instead, it uses an optical telescope, and those two units
work together to give an idea
of how much dust is in the atmosphere,
where it's moving, et cetera, et cetera.
Optical data allows scientists to start to decipher
what this dust is actually made out of.
NARRATOR: Each night,
the scientists capture a million images of
our atmosphere,
helping to decode the 100 tons of dust
that hits Earth each day.
These messages from the dawn of time could help transform
our knowledge of both our planet
and the universe around it.
LEE: The MU array is a very powerful tool
to understand the origin of our own solar system.
NARRATOR: Coming up, the maelstrom of doom.
Fishermen approach it with tremendous caution.
NARRATOR: October 31st, 2021.
A drone scans the coast of South Ayrshire in Scotland.
200 feet from shore,
it captures this in the waters below.
This drone shot is super weird.
You have this churning center, and you have this tail
that's pushing its way back out towards the sea.
It almost has this appearance of a comet
or a meteor that's headed straight for you.
NARRATOR: The head of the bizarre aquatic shape
is around 80 feet wide.
This does not look like anything I'd want to be near.
You can see next to the waves
that are breaking along the shore,
this disturbance is massive.
NARRATOR: The maelstrom sits in a patch of
ocean known for other mysterious aquatic phenomena.
Just up the coast is Corryvreckan,
one of the most powerful whirlpools on Earth.
There are tales of the whirlpool claiming the lives
of countless fishermen over the years
and the local boats approach it with tremendous caution.
NARRATOR: Guy Walters studies the footage.
He thinks that while the churning
waters do pose a threat to shipping,
they've been created by something even
more destructive.
What I'm wondering is if what we're seeing here in these
images is a legacy of the most destructive conflict in
human history -- the Second World War.
NARRATOR: Between 1939 and 1945,
British factories assemble vast
amounts of bombs and munitions for the war effort.
Following the Nazis' surrender,
authorities face the problem of what to do with more than
one million tons of unused ordnance.
WALTERS: They come up with this plan,
and it's to take all these kind of
remnants of the horrors of this global war,
and they want to put them somewhere where no one will be
able to get them, and that is at the bottom of the sea.
NARRATOR: After the war, the British
dump the munitions into Beaufort's Dyke,
a 30-mile-long sea trench near the site
in the drone footage.
CAVELL: Many of these weapons still
contain volatile explosive chemicals inside them.
So I wonder if what we're seeing here
is underwater munitions detonating on the sea floor.
NARRATOR: Analysts consult Scottish maritime records.
They discover something surprising.
Further investigations reveal that the maelstrom is
the byproduct of
a very different type of threat to the Scottish coastline.
The location of these roiling waters corresponds exactly to
the position of a runoff pipe
coming from a nearby waste landfill site.
NARRATOR: Each year, humankind dumps
two billion tons of trash into landfill sites
that can be over three square miles in size.
What's more,
by 2050, the amount of plastic we've put
in the ocean will outweigh the fish found there.
The churning waters in the footage are an attempt
to deal with another noxious byproduct
of our throwaway culture.
Landfill sites take up big areas,
so they catch a lot of rain water.
Rain water that washes down through these mountains of
trash can pick up dangerous chemicals
along the way and carry them along with the water.
NARRATOR: This toxic runoff is called leachate.
In the U.S. alone, landfill sites generate
16 billion gallons of the stuff each year,
enough to fill 24,000 Olympic swimming pools.
And much of it contains carcinogens known as
forever chemicals.
They're called forever chemicals, because once
you make them, you're kind of stuck with them.
The other thing about these forever chemicals
is that they spread easily.
They've been found in lakes, rivers, and in some states,
even in the tap water.
NARRATOR: Close to the site in the image, authorities
capture and treat these lethal chemicals in lined pools.
Clean water is then piped out to sea,
generating roiling waters, which rise to the surface.
DENNIE: As long as populations continue to grow and demand
continues to grow, we're gonna get more bad stuff.
So we've got to learn how to deal
with the bad stuff in a good way.
NARRATOR: Some studies claim that the amount of trash
we generate will triple by the end of the century.
That means we're going to see a lot more
of the strange, churning seas captured from the skies.
We have to be awake to the threat of
these chemicals that we keep throwing out,
because eventually, they might come back at us.