[explosion] <i>[dramatic music]</i> <i>male narrator:
Every corner of the planet</i> <i>has been struck by disaster.</i> [screaming] <i>But some events are
so cataclysmic...</i> [shouting] <i>They threaten...</i> - Go, go, go! <i>narrator: Our very existence.</i> <i>♪ ♪</i> <i>- It's a dangerous universe.</i> There's a lot of ways the human race can go extinct. <i>narrator: Will you be ready</i> <i>when doomsday strikes?</i> <i>Can any of us survive?</i> [screaming] <i>♪ ♪</i> <i>66 million years ago,</i> <i>a massive asteroid hit Earth</i> <i>and killed off the dinosaurs.</i> <i>What if the same-sized rock</i> <i>struck the planet today?</i> <i>Would you survive?</i> - On the scale of disasters, this would really challenge humankind to survive. [chaotic screaming] - Think of your world, and then
turn everything upside down. [screaming] You will do anything
for your loved ones. [screaming] At that point,
it's survive or die. <i>narrator:
Mount Lemmon Observatory.</i> <i>Astronomers monitor
the night sky.</i> [unintelligible chatter] <i>It's a routine evening...</i> [unintelligible chatter] <i>[eerie music]</i> <i>Until they spot something</i> <i>that catches them
completely off guard.</i> - Ma'am, you might want to take
a look at this. <i>♪ ♪</i> - This can't be right. <i>narrator: It's an asteroid
seven miles wide,</i> <i>and it's on a collision
course with Earth.</i> <i>[dramatic music]</i> - There's a small
possibility that something this large
could sneak by all the early warning systems that astronomers have in place. <i>And if that happens,</i> <i>there's this event,</i> and there's nothing we can do. <i>♪ ♪</i> <i>narrator:
Asteroids are leftover debris</i> <i>from the formation
of our solar system.</i> <i>About 100 tons of these
space rocks</i> <i>plunge into Earth's
atmosphere every day.</i> <i>Most are so small
that they burn up</i> <i>before hitting the ground.</i> <i>But larger asteroids</i> <i>pose a threat to humanity.</i> <i>Even one a half-mile wide</i> <i>could destroy a city</i> <i>and possibly
bring down civilization</i> <i>with its after-effects.</i> <i>♪ ♪</i> <i>But the asteroid
heading towards us</i> <i>is more than 14 times
that size,</i> <i>the same size as the one</i> <i>that killed off the dinosaurs.</i> <i>♪ ♪</i> <i>Falling at 43,000
miles per hour...</i> <i>There's no time
to destroy or deflect it.</i> <i>[dramatic music]</i> <i>♪ ♪</i> <i>Miami, Florida.</i> <i>It's a busy day
on South Beach.</i> <i>♪ ♪</i> [tires screech] <i>Suddenly,
an explosive light</i> <i>streaks across the sky.</i> <i>- Oh, my God.</i> - What you'd see is
a small spot in the sky that would increase
in brightness to an unimaginable amount. <i>♪</i> ♪ <i>- You would see the fireball.</i> <i>♪ ♪</i> And it would almost look like
a second sun in the sky. <i>- If you could somehow be</i> <i>right behind the asteroid</i> as it punches a hole
through the atmosphere, <i>there would be this perfect</i> <i>window to the cosmos...</i> <i>In the middle of this expanse
of daylight sky.</i> It would be like
a black hole opened up and you could see
through it into space. <i>- The atmosphere
is shock heated.</i> You're effectively opening up a rarefied channel
through the atmosphere for the several seconds
that this mountain is just booming through
the atmosphere, <i>which rapidly fills in again.</i> <i>narrator: It won't be
the last Miami sees</i> <i>of the killer asteroid.</i> <i>♪ ♪</i> <i>Over 650 miles
to the southwest,</i> <i>in Chichen Itza, Mexico,</i> <i>these Mayan temples</i> <i>were once ancient observatories</i> <i>where astronomers tracked</i> <i>the movement of the sun
and stars.</i> <i>But these ancient people</i> <i>never witnessed
anything like this.</i> - What is that? <i>narrator: As tourists
take in the temples,</i> <i>the falling asteroid
intensifies</i> <i>into a blinding light.</i> [loud booming] <i>♪ ♪</i> - Oh, my God. Oh, my God.
What is that? Oh, my God, we have to go!
We have to go! - Go! - Go!
- Go, run! Run! <i>- If you were looking up
at the place</i> <i>where the asteroid
is coming in,</i> that could burn your skin and cause even
permanent blindness <i>if you were looking
right at it.</i> - Run! <i>narrator:
The asteroid is headed</i> <i>for the Gulf of Mexico,</i> <i>over 500 miles
off the coast of Florida,</i> <i>near the Yucatan Peninsula.</i> <i>The exact spot</i> <i>where the dinosaur-killer
asteroid struck.</i> <i>Seconds later,</i> <i>impact.</i> [explosions] <i>- We're talking
the release of something like</i> <i>100 million megatons of TNT.</i> That's something like seven or
eight billion Hiroshima bombs all in one place,
all at one instant. <i>♪ ♪</i> <i>narrator:
The asteroid eats away</i> <i>at the bottom of
the ocean floor,</i> <i>creating a hole
nearly 20 miles deep</i> <i>and 100 miles across,</i> <i>as wide as the distance
from New York to Philadelphia.</i> <i>- The excavation of this
very large crater,</i> actually, to our eyes, would almost appear to happen
in slow motion. This is not a small impact that happens instantaneously
on a human timescale. <i>This happens over
several minutes.</i> [rumbling] <i>- The momentum of the impact
has pushed the rock aside,</i> and it continues to grow
and open a crater, a hole that ends up
being as large <i>as metropolitan
New York or London.</i> <i>[tense music]</i> <i>narrator: Eleven seconds
after impact,</i> <i>the energy strike produces
thermal radiation.</i> <i>Waves of intense heat travel
out in all directions</i> <i>across the surface of the Earth</i> <i>at 670 million miles per hour.</i> - Thermal radiation is just like
the infrared light that's emitted by a fire or glowing embers. <i>You're not directly seeing,</i> <i>you're just feeling it.</i> <i>♪ ♪</i> <i>narrator:
As the radiation wave</i> <i>hits Chichen Itza, Mexico,</i> <i>temperatures reach</i> <i>10,000 degrees Fahrenheit.</i> - You're going to be fried
from the impact fireball. [screaming] <i>You're talking twice
the temperature</i> <i>of the surface of the sun.</i> [screaming] <i>narrator: Anybody within
a 200-mile radius</i> <i>of the explosion</i> <i>doesn't even have
a chance to run.</i> <i>They are instantly killed.</i> <i>But the destruction
quickly spreads</i> <i>far beyond
the impact zone.</i> <i>♪</i> ♪ <i>The speed and size
of the asteroid impact</i> <i>creates such extreme
temperatures</i> <i>that it melts and vaporizes</i> <i>some of the rock
from the crater,</i> <i>which is ejected
into the atmosphere.</i> - The crystals in the rock that the impactor hits can get vaporized. And that vapor gets flung out, and then as it cools, it condenses into
glassy little spheres, and those can then get dispersed <i>throughout much of the world.</i> [explosions] <i>narrator: The debris rains
down on cities</i> <i>within about 600 miles
of the impact.</i> <i>From Houston and New Orleans</i> <i>to Mexico City,</i> <i>with its population of
20 million people.</i> <i>For anyone caught outside,</i> <i>they face almost certain death.</i> [screaming] <i>- Think sort of like
a volcanic eruption,</i> the way that
you think of material falling out of the sky. <i>[dramatic music]</i> - Mexico City would be covered with tons of ejecta
from the blast, scorching chunks of
the Earth's crust that will incinerate,
burn anything they touch. - [coughing] <i>narrator: Including humans.</i> <i>Anyone this close to the impact</i> <i>is burned or crushed</i> <i>by searing hot debris.</i> [screaming] <i>But even people in cities
farther away aren't safe.</i> <i>♪ ♪</i> <i>1,500 miles
from the point of impact...</i> <i>New York City is hit with
chunks of rock...</i> <i>And intense heat.</i> <i>- That ejecta, it's been
pulverized into smaller sizes.</i> It's entering the atmosphere at
very, very high speeds, <i>enough to actually heat
the upper atmosphere.</i> The upper atmosphere
is now radiating <i>down on you like a sun lamp.</i> <i>narrator: From Central Park</i> <i>to the mountains of Maine,</i> <i>the entire eastern seaboard</i> <i>becomes a blazing inferno.</i> - The first thing that would
happen is that the leaves would begin to steam
a little bit, <i>and then pop,
and then turn brown and smoke.</i> <i>And finally, burst into flame.</i> <i>♪ ♪</i> <i>narrator: Millions of people
have been killed</i> <i>in the initial impact.</i> As the devastation begins to<i>
spread around the world...</i> <i>Who will survive?</i> <i>And for how long?</i> - You have to adapt or die. <i>narrator: 66 million years ago,</i> <i>a massive asteroid strike</i> <i>killed off the dinosaurs.</i> <i>If an asteroid just as big
struck today,</i> <i>would you survive?</i> <i>In the Gulf of Mexico,</i> <i>over 500 miles south of Miami,</i> <i>an asteroid seven miles wide,</i> <i>the size of Mount Everest,</i> <i>has crashed into the water,</i> <i>kicking off a chain reaction</i> <i>of horrifying disasters</i> <i>across the planet.</i> [glass shattering] [screaming] - If an event the same as what killed the dinosaurs
happened today, <i>you're talking about
the near-complete</i> <i>destruction of anything</i> <i>and everything on the planet.</i> - There's no place on Earth
that is actually safe from an impact of this scale. [explosion] <i>narrator: Within minutes,
the asteroid impact</i> <i>unleashes a wave of
thermal radiation</i> <i>and sends trillions of tons</i> <i>of rocky debris</i> <i>crashing across the globe.</i> <i>[dramatic music]</i> <i>And now the Earth begins
to tremble.</i> [crashing and rumbling] <i>The asteroid strikes
the planet with such force</i> <i>that it triggers earthquakes</i> <i>that travel from
the impact site</i> <i>in all directions.</i> <i>In Los Angeles,</i> <i>a cloud of ash cloaks the city.</i> <i>Minutes later,
a massive earthquake</i> <i>shakes southern California
to its core.</i> [rumbling] <i>At a magnitude of 10.8,</i> <i>it's the most powerful
in recorded history.</i> [sirens wailing] <i>People attempt to find cover</i> <i>as thousands become trapped</i> <i>or buried alive</i> <i>under collapsing buildings.</i> <i>- Earthquakes can trigger
other earthquakes.</i> An impact that large
could trigger earthquakes <i>all around the globe.</i> [horn honking] <i>We could have cascading
earthquakes</i> <i>all the way from Mexico</i> <i>up to Alaska</i> <i>on that plate boundary.</i> <i>narrator:
Approximately 100 miles</i> <i>south of Mexico City...</i> <i>[somber music]</i> <i>A group of farmers
takes refuge from the heat,</i> <i>debris, and tremors</i> <i>in one of the largest
cave systems</i> <i>in the world.</i> <i>[dramatic music]</i> [woman crying] <i>♪ ♪</i> <i>But they're far from safe.</i> <i>♪ ♪</i> [rumbling] <i>♪ ♪</i> - If you were sheltered
inside a cave, there would be very,
very strong seismic shaking. Certainly even if the whole
cave didn't collapse, <i>you'd have rocks
falling off the ceiling.</i> <i>Your entrance would be buried
by very hot material</i> that you wouldn't
want to go near. <i>narrator: As the farmers try
and wait out the destruction,</i> <i>and earthquakes continue
to jolt the planet,</i> <i>a shockwave radiates</i> <i>from the impact site</i> <i>in all directions.</i> - You're now going to have
the blast wave, the shock wave, the compressed atmosphere that can't get out
of the way fast enough from this hypervelocity impact. <i>And that produces a--
effectively,</i> <i>a very big bomb blast.</i> <i>narrator: The blast of air
hits places</i> <i>like New Orleans
and Mexico City</i> <i>at 875 miles per hour,</i> <i>almost three times the speed</i> <i>of the fastest tornado
on record.</i> <i>For those caught
in these fierce winds,</i> <i>there is nowhere
to run or hide.</i> <i>♪ ♪</i> <i>- This supersonic wind</i> <i>could knock people
off their feet,</i> <i>and the whole city
is now covered</i> in shrapnels of glass as material continues
to fall from the sky. <i>narrator:
As daggers of glass</i> <i>rain down from buildings,</i> <i>the blast wreaks havoc
on the human body.</i> - It would be, obviously, the
loudest sound you've ever heard. <i>The concussion from an event
like that</i> is going to
burst your lungs, rupture your internal organs. You're going to die
pretty much immediately from a blast like that. <i>♪ ♪</i> <i>narrator: With many
parts of the U.S.</i> <i>either completely destroyed
or on fire,</i> <i>the shockwave and ejected
rock and dust</i> <i>now make
their way across oceans.</i> <i>♪ ♪</i> <i>Cities in Europe and Asia
are now feeling</i> <i>the asteroid's deadly effects.</i> [clock tolling] <i>In London, England,</i> <i>people flee the streets,</i> <i>under attack from the scorching
heat and debris.</i> <i>- London, like the rest
of the world,</i> would really first notice the global effects. The ejecta falling out, <i>the sky turning
bright red or white</i> <i>as thermal radiation
came down to the surface</i> <i>and set things on fire.</i> [shouting] <i>narrator: To survive
means going underground.</i> <i>Tens of thousands
of Londoners find sanctuary</i> <i>in deep-level air raid shelters</i> <i>that were last used
during World War II.</i> [people coughing] <i>- Say thousands of people
get down there.</i> They could live quite a while <i>if they had enough supplies.</i> <i>But you also have to
think about</i> <i>the human condition.</i> If your family's split up, and they're in one
air raid shelter and you're in another. <i>If you're not used
to living underground.</i> <i>You're talking about
placing a species</i> <i>that is completely used
to a singular way of life</i> into an entirely
different environment. <i>narrator: Staying underground</i> <i>seems to be
the only hope for survival.</i> <i>[dramatic music]</i> <i>As people all over the world</i> <i>seek refuge below the surface,</i> <i>how long can
they really survive?</i> [man coughing] <i>♪ ♪</i> <i>Especially when the next wave</i> <i>of the disaster hits?</i> <i>♪ ♪</i> <i>narrator: 66 million years ago,</i> <i>an asteroid impact</i> <i>wiped out most life on Earth.</i> <i>What would happen if it struck</i> <i>in the same place today?</i> <i>Would any of us survive?</i> <i>In every corner of the world...</i> [rumbling] <i>Human civilization
is under attack</i> <i>from a series of catastrophes</i> <i>triggered by
the massive impact.</i> <i>[dramatic music]</i> <i>♪ ♪</i> - So you have rocks, fire, steam, pressure, sound, earthquakes, all at the same time. It's literally an apocalypse. <i>♪ ♪</i> <i>narrator: And this is
just the beginning.</i> <i>♪</i> ♪ <i>When the mountain-sized
rock struck the Earth</i> <i>in the waters
of the Gulf of Mexico,</i> <i>it created a ring of waves</i> <i>spreading in all directions,</i> <i>producing massive tsunamis.</i> <i>♪ ♪</i> <i>Waves hundreds of feet high</i> <i>surge toward the cities</i> <i>on the Gulf Coast
of the United States,</i> <i>sending people running
for their lives.</i> <i>- We're talking about
massive waves.</i> <i>Not one, but there's
actually many waves,</i> separated by minutes, that will impact the coast
and engulf anything and everything in its way. <i>♪</i> ♪ - [pained breathing] <i>narrator: Over 650 miles
northeast of the impact,</i> <i>in Miami, Florida,</i> <i>where the asteroid
was first seen blazing</i> <i>through the sky
nine hours ago...</i> [rumbling] <i>A tsunami over 30 stories high</i> <i>now barrels
toward the city.</i> <i>♪ ♪</i> - In the peninsula of Florida,
your highest points are only, you know, maybe 100 feet
above sea level. <i>A tsunami of that magnitude
is gonna be pretty devastating.</i> <i>♪ ♪</i> <i>narrator: A wall of water
blasts through Miami</i> <i>like a wrecking ball.</i> <i>♪ ♪</i> <i>The wave churns up
broken glass and metal</i> <i>that pulverizes people
struggling to swim to safety.</i> <i>♪ ♪</i> - [screaming] [gasping] <i>narrator: And then drags them</i> <i>to a watery grave.</i> - Florida will suffer greatly. It's exposed from every side, and it's a particularly shallow
piece of land with nothing <i>that can really stand
in the way of the monster wave.</i> <i>- Cities like Miami are going
to be absolutely inundated.</i> We know from
the geologic evidence, <i>after the dinosaur-killing
impact,</i> <i>tsunamis raced inland</i> deep enough to uproot forests and drag them
back out into the Gulf. <i>[somber music]</i> <i>♪ ♪</i> <i>- If it happened today
in the same semi-shallow water,</i> <i>you would have waves
traversing the land</i> all the way into Tennessee. <i>This is covering states.</i> <i>It's covering countries.</i> <i>[dramatic music]</i> <i>♪ ♪</i> <i>narrator: After tsunamis
have ravaged the U.S. coastline</i> <i>along the Gulf of Mexico...</i> <i>Approximately 100 miles
south of Mexico City,</i> <i>the group of farmers who fled</i> <i>into one of the largest
cave systems in the world</i> <i>has survived
the immediate effects</i> <i>of the disaster.</i> <i>♪ ♪</i> <i>They dig their way
out of the cavern...</i> <i>Only to discover</i> <i>an apocalyptic wasteland.</i> <i>- Everything on Earth
is either dying,</i> <i>is on fire, or has collapsed.</i> You are walking
out of this cave system <i>into a modern hellscape.</i> - The landscape would look
like the moon. There'd be rocks everywhere. <i>It would be an utterly
devastated landscape.</i> - If you've initially
survived in the cave, <i>you're still in deep trouble,</i> <i>because now you're gonna
have to forage for food.</i> <i>The rotting corpses of animals
that were killed.</i> Probably any vegetation
on the surface is gonna be un-edible. [explosion] <i>narrator: Within one week
of the asteroid strike,</i> <i>the farmers' chance
of survival looks grim,</i> <i>and they're not alone.</i> <i>♪ ♪</i> <i>Even thousands of miles
from the impact site,</i> <i>the populations of
Beijing, Moscow, and Cairo</i> <i>are under fire from
the heat and debris</i> <i>that continue to rain down.</i> [screaming] <i>A quarter of
the world's population</i> <i>is already dead.</i> <i>♪ ♪</i> <i>Can mankind hold out?</i> <i>Or is this the beginning
of the end?</i> <i>narrator: What if an asteroid
as massive as</i> <i>the one that
killed the dinosaurs</i> <i>66 million years ago</i> <i>struck in the same place today?</i> <i>[dramatic music]</i> <i>Could mankind survive?</i> <i>♪ ♪</i> [screaming] <i>Already the Gulf Coast
of the US and Mexico</i> <i>has been ripped apart
by a hail of hot debris,</i> <i>shockwaves, and tsunamis.</i> <i>♪ ♪</i> <i>Southern California
and parts of Asia</i> <i>have been rocked by earthquakes</i> <i>and searing temperatures.</i> <i>Nearly two billion people
have already died.</i> <i>And most survivors</i> <i>are hanging on by a thread.</i> [woman crying] <i>But the devastation</i> <i>has only just begun.</i> <i>- This isn't just flash
and it's done.</i> <i>The secondary effects
could cause</i> even longer-lasting damage. If you survived
the initial impact, you would be stepping out into a hellscape of absolute chaos. And unless you're prepared
for it, you're going to die. <i>♪ ♪</i> <i>narrator: When the asteroid
slammed into the ocean floor,</i> <i>it ejected rock
containing toxins</i> <i>that become potent
as battery acid.</i> - Sulfur-containing compounds released to the atmosphere
combining with rainwater are gonna make
sulfuric acid rains. [thunder clapping] - The acid rain would do
a huge amount of damage to everything on the planet. [wind whistling] <i>Buildings would corrode.</i> <i>Plants would die.</i> <i>Rivers would be clouded,
full of material.</i> <i>Most reservoirs
would be undrinkable.</i> <i>You would have to have some</i> amazing water filtration systems to even begin to think
about survival at this point. <i>[tense music]</i> <i>narrator: In Los Angeles,
one week after the impact,</i> <i>survivors are still recovering
from the massive earthquake</i> <i>that almost leveled the city.</i> <i>♪ ♪</i> <i>They now must battle
toxic dust,</i> <i>aerosols, and acid rain.</i> <i>♪ ♪</i> <i>- If you were
to survive long enough,</i> and you were to come out
of your shelter or anything like that, you'll have to have
protective equipment. You'll have to have goggles
from all the dust in the air. <i>You'll have to have
a filtration system,</i> <i>a respirator.</i> <i>♪ ♪</i> <i>narrator: The combined effects
of dust, smoke, and acid rain</i> <i>do more than pollute
the air and soil.</i> <i>They almost completely
block out the sun's rays.</i> [thunder rumbling] <i>[somber music]</i> <i>Without sunlight,</i> <i>plant photosynthesis stops.</i> <i>Without crops,</i> <i>animals will die.</i> <i>And without plants and animals,</i> <i>people will perish.</i> <i>♪ ♪</i> <i>- Effectively, the whole
food chain is broken.</i> We know that the extinction
nearly 66 million years ago was a global event, because beyond just
the dinosaurs dying, we know that roughly 2/3
of all species of life perished throughout the world. And so this impact had to have global consequences. - Changing the
atmospheric composition, <i>that's gonna severely
affect agricultural plants.</i> <i>There's gonna be
a lot of people</i> <i>out trying to scavenge food</i> <i>beyond their
local supermarkets.</i> <i>That's for sure.</i> <i>[dramatic music]</i> <i>- You will do anything
for your loved ones.</i> - Let's go. [commotion] - That includes instituting
survivalist tribal war to try and get someone
else's resources. - Go! <i>- At that point,
it's survive or die.</i> <i>♪ ♪</i> <i>narrator: Nearly 11,000 miles
away from the impact site,</i> <i>in the rural western
desert of Australia,</i> <i>the Martu,</i> <i>a group of
aboriginal Australians,</i> <i>are one of the oldest
and most resilient cultures</i> <i>in the world,</i> <i>with roots dating back
40,000 years.</i> <i>♪ ♪</i> <i>But they've never encountered</i> <i>a mysterious disaster
like this.</i> <i>The lingering acid rain
wreaks havoc on the landscape,</i> <i>and slowly kills off
their main food source:</i> <i>kangaroo.</i> <i>[tense music]</i> <i>But the Martu are resourceful.</i> <i>♪ ♪</i> <i>They set small bush fires</i> <i>to expose the burrows
of lizards.</i> <i>♪ ♪</i> <i>Small lizards also survived</i> <i>the asteroid impact
66 million years ago,</i> <i>because they lived underground</i> <i>and fed on insect larvae</i> <i>such as beetles
and cockroaches,</i> <i>which also escaped extinction.</i> <i>- The aboriginal people
may fare fairly well.</i> They are used to rooting out, almost literally, food sources. [shouting in native language] <i>They're used to
hunting and gathering,</i> <i>and having a deep knowledge
of the world</i> <i>in a way that
city dwellers don't.</i> <i>♪ ♪</i> <i>narrator: But while the Martu
use primitive hunting skills</i> <i>to try to stay alive...</i> - Get it.
Get it. <i>narrator: Other humans
are faced with</i> <i>an environmental
ticking time bomb</i> <i>that threatens
our existence forever,</i> <i>as the Earth turns
from fire</i> <i>to ice.</i> <i>♪ ♪</i> <i>narrator: Could mankind survive</i> <i>a massive asteroid impact</i> <i>like the one
that killed off the dinosaurs</i> <i>66 million years ago?</i> <i>[dramatic music]</i> <i>Six months after
a devastating asteroid strike,</i> <i>human life on Earth
hangs by a thread.</i> <i>♪ ♪</i> <i>Some are living
in bomb shelters</i> <i>and basements.</i> <i>Others are living in caves.</i> <i>All are in grave danger,</i> <i>as things are about
to get worse.</i> <i>A blanket of dust
and aerosols is having</i> <i>a chilling effect
on the climate.</i> <i>♪</i> ♪ <i>Due to the absence of sunlight,</i> <i>the world is plunged
into a deep freeze,</i> <i>an impact winter.</i> <i>♪ ♪</i> - The amount of particulate
that will be thrown in the air during an asteroid impact
is enough to cool the planet
extremely rapidly, days, weeks, months. <i>Because of that, temperatures
will absolutely drop.</i> [wind swirling] <i>- It's a perfect double-whammy.</i> First, the hot fire. And now, freezing temperatures. It would bring many species
to the edge of existence. [wind blowing] <i>narrator: Around the globe,</i> <i>the average temperature
plummets</i> <i>nearly 13 degrees.</i> <i>[tense music]</i> <i>It's a worldwide chill</i> <i>that reaches extremes
in places like London,</i> <i>where the spring temperatures</i> <i>are 50 degrees Fahrenheit
below normal.</i> <i>♪ ♪</i> <i>The air raid shelters,</i> <i>where tens of thousands
had taken refuge,</i> <i>have become mass graves.</i> <i>[suspenseful music]</i> <i>♪ ♪</i> <i>The survivors have no choice</i> <i>but to brave the elements</i> <i>in search of food and water,</i> <i>trying not to become
the final victims</i> <i>of a new mass extinction.</i> <i>- You're dealing
with no sunlight.</i> <i>No animals on the surface
of the planet.</i> <i>You'd have to dig down
for them.</i> <i>You'd have to be
comfortable eating them.</i> Not a whole lot of people
are like that, unfortunately. <i>[dramatic music]</i> <i>♪ ♪</i> <i>narrator: One year after
the asteroid impact,</i> <i>the toxic dust begins to</i> <i>dissipate across the globe...</i> <i>♪ ♪</i> <i>Allowing the sun's rays
to reach</i> <i>the Earth's surface
once again.</i> <i>♪ ♪</i> <i>But with this,</i> <i>another danger
awaits the survivors.</i> <i>♪ ♪</i> <i>The Earth's ozone layer,</i> <i>an atmospheric shield
in the planet's stratosphere,</i> <i>is completely destroyed.</i> <i>♪ ♪</i> <i>- The impact would eject
a lot of compounds</i> <i>that would react
with Earth's ozone layer</i> in the upper atmosphere,
destroying them. And then the sun's
ultraviolet radiation would be much more likely to <i>penetrate through
Earth's atmosphere,</i> <i>react with our living cells,</i> <i>and cause mutations,</i> <i>most of which are hazardous
to our health.</i> - [groaning] <i>- If you get too much
ultraviolet radiation,</i> it causes all sorts of
biological damage. You can get skin cancers.
You can get burns. <i>It causes cataracts.</i> <i>♪ ♪</i> <i>narrator: In Los Angeles,
London, Mexico City,</i> <i>and other places
around the world,</i> <i>ozone depletion isn't
the only new danger.</i> <i>Once the dust and toxins
have settled,</i> <i>temperatures begin to rise</i> <i>due to the enormous amount
of carbon dioxide</i> <i>that has been released.</i> <i>♪ ♪</i> <i>- You'd have
an increased warming,</i> <i>an elevated greenhouse effect.</i> <i>♪ ♪</i> <i>Because various
limestone-type rocks</i> <i>would've been vaporized
by the impact.</i> That would send the carbon
dioxide into the atmosphere. <i>- It circulates
around the planet.</i> Temperature rises as much as maybe 10 or even
12 degrees globally. <i>♪</i> ♪ [fire crackling] <i>narrator: As temperatures
become unbearably hot,</i> <i>the last few survivors</i> <i>cling to life.</i> <i>♪ ♪</i> <i>narrator: 66 million years ago,</i> <i>a massive asteroid
struck planet Earth,</i> <i>leading to the extinction
of the dinosaurs.</i> <i>Could humans survive</i> <i>if the same thing
happened today?</i> [explosion] <i>[dramatic music]</i> <i>♪</i> ♪ <i>Two years after
the asteroid impact,</i> <i>life on Earth is enduring</i> <i>the worst disaster
in human history.</i> <i>♪ ♪</i> <i>At least half
the world's population</i> <i>of 7 billion has perished.</i> - There's gonna be
so much devastation and so much chaos that it's gonna be
"Mad Max" world. <i>No person alive on the planet
at the time of the impact</i> <i>will ever see
a normal life after that.</i> <i>♪ ♪</i> <i>narrator: For humans
around the world,</i> <i>animals that were once
feared and avoided</i> <i>are now the keys
to survival.</i> <i>♪ ♪</i> <i>100 miles south of Mexico City,</i> <i>a dwindling group
of farmers</i> <i>clings to life inside a cave,</i> <i>subsisting on a diet of</i> <i>bats, rats, and snakes,</i> <i>all descendants of species</i> <i>that survived the asteroid</i> <i>that killed the dinosaurs.</i> <i>The limestone
bedrock neutralizes</i> <i>the acid rain deposits</i> <i>in the cave's river water,</i> <i>making it safe to drink.</i> - If you manage to find
the perfect cave that you could light a fire, and have all of
the carbon monoxide escape through vents to the surface. <i>If you had different caverns,
say, with bats,</i> <i>and rats, and bugs
that you could eat.</i> <i>If you have to be
in there long enough,</i> <i>it's a lot more than just</i> <i>food, shelter, and water
to think about.</i> The human psyche will really
have a massive impact on any kind of survivability. <i>♪ ♪</i> <i>[suspenseful music]</i> <i>narrator: Over 1,500 miles
to the north,</i> <i>in New York City,</i> <i>sparse pockets
of humanity sleep</i> <i>in the day to avoid
the harsh environment outside.</i> <i>♪ ♪</i> <i>They troll subways and alleys
at night</i> <i>hunting for rats and possum.</i> <i>♪ ♪</i> <i>But we are not built
for a nocturnal existence.</i> <i>- As humans,
we need vitamin D.</i> Vitamin D is best synthesized
in the human body by being exposed to the sun. If there is no sun, <i>we begin turning into
a nocturnal lifestyle,</i> <i>like mole people.</i> <i>You start losing hair.</i> <i>Your liver isn't
functioning very well.</i> <i>Your skin begins
to reduce its melanin.</i> <i>And if you have to live
in there for generations,</i> <i>you have these weird,</i> <i>pasty white people
who are blind.</i> <i>♪ ♪</i> <i>narrator:
Halfway around the world,</i> <i>the aboriginal Martu</i> <i>have migrated to
the west coast of Australia.</i> [fire crackling] <i>They spend much of the day
in coastal caves,</i> <i>protected from the UV rays</i> <i>and searing heat.</i> <i>At dusk, they hunt for turtles,</i> <i>one of the few marine creatures</i> <i>that have endured the disaster.</i> <i>- Turtles survived the impact
65 1/2 million years ago</i> <i>because they are great
at adapting.</i> They can survive huge temperature variations,
acidity levels. <i>They could eat dead carcasses.</i> <i>They could eat seaweed</i> <i>and anything falling
through the water column.</i> <i>narrator: By relying on
creatures like these</i> <i>for food,
the Martu will be among</i> <i>the last survivors
on planet Earth.</i> <i>[tense music]</i> <i>But the asteroid impact
will decimate</i> <i>the human population
as a whole.</i> <i>♪ ♪</i> <i>66 million years ago,</i> <i>when the first killer
asteroid hit...</i> <i>Most land creatures</i> <i>weighing over 30 pounds
went extinct,</i> <i>which means
the long-term outlook</i> <i>for humanity is grim...</i> <i>♪ ♪</i> <i>Leaving the very existence
of our species in doubt.</i> - I would guess
something like 99% of the human population
would die in such an event. <i>- Long-term?</i> Say 10%
of all of humanity lives. Then you have
a genetic bottleneck <i>that may not be
a viable population.</i> <i>It gets to a point where,
all of a sudden,</i> <i>you're the last group
of people on Earth.</i> <i>And if that happens,</i> <i>you may survive
for a generation or two.</i> Our intellect is our tool. That is our evolutionary edge. But we've lost <i>the kind of necessary,</i> <i>natural tools to use</i> <i>in a situation like this.</i> <i>[dramatic music]</i> <i>The next great extinction</i> <i>likely will be us.</i>
