Original subtitles

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.

This is the story of the fall of the dinosaurs...

and the rise from the ashes

of the survivors who would inherit the Earth.

Our story begins in the Cretaceous period...

...on a day that would change the course of history.

For Edmontosaurus in North America, it's nesting season.

As usual, this female must tend to her hungry young...

...giving them the best possible start in life.

A thousand kilometers south,

an adult tyrannosaur...

...is teaching her offspring the art of the hunt.

But they're a little impatient.

The youngsters still have a lot to learn.

Perhaps they'll have more luck tomorrow.

To the west, a herd of Alamosaurus...

...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.

Along with the dinosaurs,

they have ruled planet Earth for a staggering 150 million years.

But today will be a day like no other.

An asteroid the size of Mount Everest

is tumbling towards Earth at 100,000 kilometers per hour.

Its impact will change the world forever...

...unleashing the power of a billion atomic bombs...

setting in motion a devastating chain of events.

First comes a deadly blast of thermal radiation.

Every living thing within a thousand kilometers

is vaporized in a matter of seconds.

The planet's crust buckles from the impact,

sending seismic shock waves around the world.

In mere minutes...

...off-the-scale earthquakes rock the globe.

For the Alamosaurus...

this is just the beginning.

The earthquakes trigger a series of giant waves

that rip through seas and inland lakes.

Huge surges of water sweep across North America.

The rapidly rising torrent is impossible to withstand,

even for the mightiest.

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.

On the ground, it's like standing under a 400-degree grill.

Animals are slowly cooked alive.

To make matters worse, the rock debris starts to rain down.

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.

Nothing can save them now.

The great reign of the dinosaurs,

over in a single day.

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.

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.

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.

Against the odds, another group of animals had also clung on...

...protected by their very own life-support capsules.

Remarkably, inside them

was a type of dinosaur.

More specifically, an avian dinosaur...

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.

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.

From such humble creatures,

a great dynasty would rise.

But their incredible story first began long, long before the asteroid.

The Jurassic.

An era of giants.

But this lost world of vertical cliffs

was shaping a smaller breed of creature.

It lived in a dangerous realm.

To survive, it had evolved in an extraordinary new way.

This is Anchiornis.

She's a small, feathered dinosaur...

...with needle-sharp teeth for hunting insects.

But she, too, is being hunted.

A juvenile Sinraptor.

And he's hungry.

Anchiornis is slow and clumsy.

The Sinraptor has her cornered.

But Anchiornis...

...has run here for a reason.

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.

And it was flight that would help their descendants stay alive

in the era after the asteroid.

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...

...flamingos have taken the gliding skills of the first avian dinosaurs...

...and created a new kind of flight.

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...

...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.

Courtship.

For the flamingos,

that means a dance-off...

and it's taken very seriously.

The judges are extremely fussy.

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.

But their path would not be easy.

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.

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.

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.

But just five million years after the asteroid,

the pine forest became home to a new breed of creature.

And they still haunt our forests today.

The owls.

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.

Able to fly in near silence, she listens for prey.

For tiny mammals, nowhere is safe.

While the first owls were menacing the northern pine forests,

elsewhere, another important habitat was emerging.

The asteroid had wiped out three-quarters of all Earth's plant and animal species.

In the tropics, it took six million years,

but life did eventually return.

However, this time, it was totally different.

The revival was powered by a huge increase...

in the diversity of flowering plants.

Richer than anything that had gone before...

...the tropical rainforests.

This thriving habitat

was built on the close relationship between flowers

and their insect pollinators.

But there was a new arrival...

...who muscled in on the insect's domain.

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.

To plunder the nectar,

they've evolved to hover just like insects...

...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.

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.

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.

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.

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...

...since Tyrannosaurus rex.

Stalking among the glades of palms...

...it has inherited the most aggressive traits

from its ancient bloodline.

In the clearing, a herd of early mammals graze.

Theosodon, about the size of a modern-day llama.

An adult female keeps a keen watch.

But she hasn't seen...

the terror bird.

With a head like a pickaxe and standing two and a half meters tall,

it sacrificed flight for raw power.

She senses something is wrong.

But the terror bird moves in near silence.

The hunt is on.

Able to rapidly accelerate to 50 kilometers an hour...

he's picked out a youngster

trailing behind.

Using the weight of his giant head,

he's a master at changing direction.

Time to deliver the final blow.

The savage terror birds now dominated the plains of South America.

But on the other side of the world,

the ever-shifting continents were writing a new chapter

in the story of life.

Australia had been heading north for millions of years.

As it did so, it created a vast shallow sea.

A new cradle of life.

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.

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.

Yet again, the birds.

More specifically, seabirds.

Millions of years ago,

they found a spectacular way to plunder the ocean's bounty...

...with an aerial invasion.

And it's still happening today.

The greatest invaders of them all...

...are the gannets.

Their keen vision means they can spot a ball of fish a mile away.

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.

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.

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.

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.

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...

...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.

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.

But these apex predators would soon become the prey.

Other survivors of the asteroid had also been evolving.

No longer in the shadow of the dinosaurs...

...they'd grown bigger and more dangerous.

It was time for the rise

of the mammals.