[ominous music playing]
[Morgan Freeman] It's winter...
but like none the world has ever known.
This is a post-apocalyptic winter.
Sixty-six million years ago,
and the world has all but been destroyed
by a cataclysmic event.
[mournful vocalizing]
This is the story of the fall of the dinosaurs...
and the rise from the ashes
of the survivors who would inherit the Earth.
[squawking]
[music ends]
[rousing music playing]
[snarling]
[trilling]
[screeching]
[rousing music continues]
[growling]
[wind howling]
[rumbling]
[rousing music intensifies]
[music fades]
[mournful vocalizing]
Our story begins in the Cretaceous period...
[grunting]
...on a day that would change the course of history.
[gentle music playing]
For Edmontosaurus in North America, it's nesting season.
As usual, this female must tend to her hungry young...
[brays]
[mewling]
...giving them the best possible start in life.
[mewling]
[adult brays]
[majestic music playing]
A thousand kilometers south,
an adult tyrannosaur...
[snorts]
...is teaching her offspring the art of the hunt.
But they're a little impatient.
[snarling]
[grunting]
[snorting]
[roaring]
The youngsters still have a lot to learn.
Perhaps they'll have more luck tomorrow.
[birds tweeting]
[majestic music continues]
To the west, a herd of Alamosaurus...
[bellows]
...some of the largest dinosaurs to have ever lived,
begin their day as they have for generations,
enjoying tender pine shoots.
Below the waves, off the coast of Africa,
the oceans are bountiful, bursting with life...
a realm dominated by huge marine reptiles.
[majestic music continues]
Along with the dinosaurs,
they have ruled planet Earth for a staggering 150 million years.
[animals calling]
[snarling]
But today will be a day like no other.
[music ends]
An asteroid the size of Mount Everest
is tumbling towards Earth at 100,000 kilometers per hour.
Its impact will change the world forever...
[ominous music playing]
...unleashing the power of a billion atomic bombs...
setting in motion a devastating chain of events.
First comes a deadly blast of thermal radiation.
[roaring]
Every living thing within a thousand kilometers
is vaporized in a matter of seconds.
[explosive blast]
[rumbling, hissing]
[high-pitched whine]
[explosive blast]
The planet's crust buckles from the impact,
sending seismic shock waves around the world.
In mere minutes...
[braying]
...off-the-scale earthquakes rock the globe.
[grunting]
[rumbling]
[bellowing]
For the Alamosaurus...
this is just the beginning.
[bellows]
The earthquakes trigger a series of giant waves
that rip through seas and inland lakes.
[animals calling]
Huge surges of water sweep across North America.
[epic, mournful music playing]
The rapidly rising torrent is impossible to withstand,
even for the mightiest.
[bellowing]
Less than an hour after impact,
debris ejected into space is pulled back to Earth by gravity.
On re-entry, it turns scorching red-hot.
The super-heated atmosphere advances like a fiery hell.
[epic, mournful music continues]
On the ground, it's like standing under a 400-degree grill.
[screeching]
Animals are slowly cooked alive.
[screeching]
[grunting, screeching]
[infants mewling]
To make matters worse, the rock debris starts to rain down.
[screeching]
Less than two hours after impact,
the firestorm of choking dust has enveloped half the planet.
It's so hot,
trees burst into flames.
The growing inferno is impossible to escape.
[grunting]
[squawking]
[wind whistling]
[mournful vocalizing]
[groaning]
Nothing can save them now.
[screeching]
[mournful vocalizing continues]
The great reign of the dinosaurs,
over in a single day.
[thunder crashing]
The oceans were just as devastated as the land.
Sulfur-rich dust poured down as acid rain.
Ancient reefs were obliterated.
The web of life collapsed,
killing off the great marine reptiles.
Their bodies provided a lifeline for scavengers,
searching out death in the deep.
Arthropods.
Sharks.
Away from the carnage of the asteroid,
many life-forms survived,
devouring the immense carcasses...
feasting on extinction.
But back on the surface, the picture couldn't have been more different.
For years after the impact,
Earth looked dead.
[mournful vocalizing resumes]
The forests,
the plains...
the mountains...
lifeless.
But as the dust cloud dispersed...
and the light finally returned...
it became clear that all was not lost.
The insects were some of the first to emerge...
feeding on the fallen.
Survivors were protected by burrows...
cocoons...
and armored bodies.
Sheltering below ground...
some reptiles survived too.
[intriguing music playing]
[croaks]
Beneath the surface of river deltas and wetlands,
others were also shielded from the mayhem.
The amphibians.
With little food around,
only small creatures had made it...
including from our dynasty,
the mammals.
They'd inherited a planet free of dinosaurs.
Or so it seemed.
[music fades]
Against the odds, another group of animals had also clung on...
[suspenseful music playing]
...protected by their very own life-support capsules.
Remarkably, inside them
was a type of dinosaur.
[chirping]
More specifically, an avian dinosaur...
[chirping]
otherwise known as the birds.
Before the apocalypse,
there had been hundreds of ancient species living in the trees,
all wiped out when the forests burned.
[chirping]
But a handful of ground-dwelling birds did make it through.
These survivors were kept warm by feathers...
and were self-sufficient from their first breath...
able to live on insects and seeds
and capable of walking within hours.
Sixty-six million years ago,
birds had become the last remaining branch of the dinosaur family tree.
[chirping]
From such humble creatures,
a great dynasty would rise.
But their incredible story first began long, long before the asteroid.
The Jurassic.
[bellows]
An era of giants.
[bellowing]
But this lost world of vertical cliffs
was shaping a smaller breed of creature.
-[tense music playing] -It lived in a dangerous realm.
[low growling]
To survive, it had evolved in an extraordinary new way.
[squawks]
This is Anchiornis.
[squawks]
She's a small, feathered dinosaur...
[squawks]
...with needle-sharp teeth for hunting insects.
[squawking]
But she, too, is being hunted.
[ominous music playing]
[snorting]
A juvenile Sinraptor.
[snorts]
[squawking]
And he's hungry.
[squawks]
[ominous music intensifies]
[squawks]
[grunts]
[squawks]
[dramatic music playing]
[screeching]
Anchiornis is slow and clumsy.
[snarling]
[Sinraptor snarling]
The Sinraptor has her cornered.
-[squawks] -[Sinraptor snarling]
But Anchiornis...
[Sinraptor snarling]
...has run here for a reason.
[tense music playing]
[snarling]
-[screeches] -[roars]
[stirring music playing]
She can fly.
One small step for a dinosaur,
but one giant leap for life on Earth.
With these early gliders, a new dynasty was born.
[screeching]
And it was flight that would help their descendants stay alive
in the era after the asteroid.
[ominous music playing]
Today, there's a place where we can see how that story may have played out.
It's a harsh, desolate world.
Four thousand meters up, the Altiplano desert in Chile...
a landscape where almost nothing can live.
But one group of animals has found a way to survive here.
The birds.
Like those that evolved after the asteroid...
[trilling]
...flamingos have taken the gliding skills of the first avian dinosaurs...
[graceful music playing]
...and created a new kind of flight.
[trilling]
A revolution in the air.
Wings that have been modified to flap.
This is powered flight,
and it allows flamingos to travel in search of food...
just as birds did millions of years ago.
Feathers, that first evolved to keep dinosaurs warm,
have become specialized for aerial mastery.
And that's not the only change.
Teeth have been replaced by beaks...
[trilling]
...that allow them to feed on new diets.
But advances in feeding and flight alone
were not enough to ensure the future of the birds.
They also drew on a rather flamboyant ancient behavior,
a behavior that ensures the survival of the fittest.
[lively music playing]
-[trilling] -Courtship.
For the flamingos,
that means a dance-off...
and it's taken very seriously.
The judges are extremely fussy.
[lively music continues]
And they need to be to choose the best mates.
Birds had almost been wiped out with the rest of the dinosaurs.
Instead, thanks to their feathery talents,
they'd have a chance to rise.
[trilling]
[music fades]
But their path would not be easy.
[wind howling]
In the aftermath of the asteroid,
global temperatures plunged by a staggering 25 degrees.
But thanks to their ability to survive the cold,
just a few million years after the impact,
the pine forests had returned.
[poignant music playing]
Seeds ensured that the giant conifers from the days of the dinosaurs
made it through.
The greatest of them all, reaching over 100 meters into the air,
were the redwoods.
[slow, majestic music playing]
Sheltered beneath the forests
was a group of warm-blooded animals
that had long hidden in the shadows.
The mammals.
At first, they were small creatures,
similar to voles.
With the dinosaurs gone, they were free to come out in the open.
[ominous music playing]
But just five million years after the asteroid,
the pine forest became home to a new breed of creature.
[ominous music continues]
And they still haunt our forests today.
[squeaks]
The owls.
[dramatic music playing]
Birds had turned from mere survivors into predators.
This is the great gray owl.
She's armed with razor-sharp claws
and even sharper eyesight...
making her deadly on the wing.
[music fades]
Able to fly in near silence, she listens for prey.
[tense music playing]
For tiny mammals, nowhere is safe.
[music fades]
[vole squeaking]
[squeaking]
-[crunching] -[squeaking]
While the first owls were menacing the northern pine forests,
elsewhere, another important habitat was emerging.
[poignant music playing]
The asteroid had wiped out three-quarters of all Earth's plant and animal species.
[rumbling]
In the tropics, it took six million years,
but life did eventually return.
However, this time, it was totally different.
[slow, uplifting music playing]
The revival was powered by a huge increase...
in the diversity of flowering plants.
[uplifting music intensifies]
Richer than anything that had gone before...
[chirping]
[croaking]
...the tropical rainforests.
This thriving habitat
was built on the close relationship between flowers
and their insect pollinators.
[buzzing]
But there was a new arrival...
[humming]
...who muscled in on the insect's domain.
[lively music playing]
Using incredible flying skills,
they could navigate the complex world of the jungle.
They'd become miniature,
granting them access
to the flower's sweet nectar.
And their descendants are still at it today.
The hummingbirds.
[humming]
To plunder the nectar,
they've evolved to hover just like insects...
[birds tweeting]
...beating wings at 80 times a second.
Elongated beaks allow them to feed on a kaleidoscope of different flowers.
The hummingbirds outmaneuver many of their insect rivals.
But all this activity comes with a huge thirst for energy.
So the best flowers are worth fighting for.
[loud humming]
Beaks double as weapons.
But one species of hummingbird has no need to battle.
It has an extraordinary adaptation that leaves the competition standing.
Enter the swordbill.
[lively music playing]
He boasts an impressively long appendage.
His beak is like a key in a lock,
so only he can enjoy the hard-to-reach nectar
of the angel trumpet flower.
In the ages following the apocalypse,
giant dinosaurs may have no longer roamed the forest,
but their tiny cousins had recolonized them
in a completely new way.
[humming]
[music ends]
But becoming small wouldn't work in every part of the planet.
The death of the dinosaurs
had left many of Earth's great habitats free for the taking.
[animals calling]
None more so than the plains.
And in early South America, 46 million years after the asteroid,
ground-dwelling birds
had the space to evolve into the deadliest predator...
[shrieking]
...since Tyrannosaurus rex.
Stalking among the glades of palms...
[shrieking]
...it has inherited the most aggressive traits
from its ancient bloodline.
[shrieking]
[mewling]
[lowing]
In the clearing, a herd of early mammals graze.
[bleats]
Theosodon, about the size of a modern-day llama.
An adult female keeps a keen watch.
But she hasn't seen...
the terror bird.
[sinister music playing]
With a head like a pickaxe and standing two and a half meters tall,
it sacrificed flight for raw power.
[whimpers]
She senses something is wrong.
But the terror bird moves in near silence.
[herd lowing]
[lowing]
[suspenseful music playing]
[trilling]
The hunt is on.
Able to rapidly accelerate to 50 kilometers an hour...
he's picked out a youngster
trailing behind.
[trilling]
[terror bird trilling]
Using the weight of his giant head,
he's a master at changing direction.
[dramatic music playing]
[herd screeching]
[trilling]
[music fades]
[Theosodon squealing]
[bleats]
[braying]
Time to deliver the final blow.
[screeching]
The savage terror birds now dominated the plains of South America.
[roars]
-[trilling] -[howling]
But on the other side of the world,
the ever-shifting continents were writing a new chapter
in the story of life.
[ethereal vocalizing]
Australia had been heading north for millions of years.
As it did so, it created a vast shallow sea.
A new cradle of life.
[ethereal ambient music playing]
Part plant...
part animal...
these are the corals.
Using energy from the Sun,
they formed the largest living structure our planet has ever seen...
the tropical reefs.
[ethereal music playing]
Fifteen million years ago, these giant marine cities
offered opportunity to a wealth of survivors.
From the depths came the sharks.
The reefs also drew in some of the last remaining marine reptiles...
the turtles.
Within this underwater paradise,
countless new kinds of fish also evolved.
The growing abundance soon spilled out to the wider ocean...
filling it with life.
And this had not gone unnoticed...
by one relentless dynasty.
[music fades]
[squawking]
Yet again, the birds.
More specifically, seabirds.
[squawking]
Millions of years ago,
they found a spectacular way to plunder the ocean's bounty...
[majestic music playing]
...with an aerial invasion.
[squawking]
And it's still happening today.
The greatest invaders of them all...
[squawking]
...are the gannets.
Their keen vision means they can spot a ball of fish a mile away.
[energetic music playing]
Diving from altitude,
they pierce the surface at close to 90 kilometers an hour.
A specially adapted skull
and retractable wings
turn them into living missiles.
What's more,
gannets can hold their breath for more than 40 seconds.
These ancient seabirds are master hunters.
Their aerial assault
allows them to compete with the ocean's greatest predators,
the sharks.
Feeding frenzies like these are still some of nature's grandest spectacles,
just as they were 15 million years ago.
Dinosaurs never conquered the oceans,
but their avian descendants finally found a way.
[music fades]
[squawking]
Their conquest of the seas was so successful,
seabirds established vast colonies across the planet...
now some of the most incredible gatherings of life on Earth.
But the birds' triumph over the oceans was not quite complete.
Their crowning achievement
can best be seen in a world lost in time.
[ominous music playing]
The Galápagos Islands.
These are marine iguanas,
descendants of lizards that survived the asteroid.
Like most reptiles, they must bask in the sun to warm up.
But they're not the only sunbathers here.
They're joined by an extraordinary bird.
The penguin.
[squawks]
And this is the Galápagos penguin.
Over tens of millions of years, its ancestors repurposed their wings,
fine-tuning them to no longer fly in the air,
but to pull off something remarkable...
beneath the waves.
[serene music playing]
Underwater flight.
Penguins have sublime buoyancy control...
and one of the most streamlined bodies of any animal,
making them the world's greatest swimming birds.
Scanning for fish, it hovers like a hummingbird...
with perfect poise.
In contrast, the cold-blooded iguanas are slow and sluggish...
restricted to feeding on low-energy kelp...
at the whim of the currents.
The warm-blooded penguins couldn't be more different...
with their speed and agility...
chasing down fish with ease.
Underwater flight
allowed the penguins to exploit the seas like never before.
Their strategy has been so successful,
they've colonized all the continents of the Southern Hemisphere...
[chattering]
...evolving into the 18 different species we know today.
The final epic chapter for the birds,
a dynasty that was almost wiped out.
But thanks to the few survivors of the dinosaur family tree,
birds rose from the ashes.
Over 66 million years,
they've reinvented themselves into a myriad of forms.
[chirping]
Today, 10,000 species strong,
they've found a way to thrive in almost every corner of the planet.
But they are not the only ones to have conquered the world.
Not so long ago,
the Americas were still at the mercy of the terror birds.
[roaring]
But these apex predators would soon become the prey.
[roaring]
Other survivors of the asteroid had also been evolving.
No longer in the shadow of the dinosaurs...
[roaring]
...they'd grown bigger and more dangerous.
[snarling]
[screeching]
-[growling] -[screeching]
It was time for the rise
of the mammals.
[snarling]
[roars]
[rousing music playing]