In the depths of space,
a threat is looming.
Trapped between the orbits of Jupiter and Mars…
the asteroid belt.
One and a half million chunks of ancient rock,
circling the sun.
Drifting endlessly.
But, in a single moment of pure chance…
…one asteroid is thrown out of its orbit.
A fleeting instant,
millions of kilometers from Earth,
sends it on a new trajectory
towards the very center of our solar system.
But its journey will come to a sudden and violent end,
in one of the most catastrophic events in Earth's history.
And the final chapter
in the epic story
of the dinosaurs.
It's three million years
since the asteroid started its journey towards Earth.
And the dinosaurs rule the planet.
They dominate the land and are now entering the ocean as well.
The high sea levels have split North America in two…
creating endless coastlines…
hundreds of tropical islands…
and opportunity.
But these islands are no paradise.
They are home to a formidable predator.
One of the fastest, most agile dinosaurs of its kind.
North America's answer to the Spinosaurus.
Just not in the way you would think.
Not even remotely.
This is Hesperornis.
He is formidable, and he is fast.
But he's pretty much the opposite of his giant, terrifying cousins.
He's awkward…
…and clumsy.
And has tiny teeth.
Not exactly the traits of a ferocious hunter.
But what he does share with Spinosaurus
is that he's not confined to dry land.
In fact, he's the most advanced aquatic dinosaur in history.
Like some sort of prehistoric penguin,
he's able to swim far out to sea to access feeding grounds
that were previously out of reach.
This is the bounty of his new blue realm.
Down here, his big clumsy feet become powerful propellers.
And his 94 needle-sharp teeth snatch fish with ease.
But as an air-breather,
he's still tied to the surface.
And the surface is not a safe place to linger.
Because below,
there are beasts
twice the size of a killer whale.
Mosasaurs.
The apex predators of these seas.
Hesperornis must get back to the shore.
But the mosasaur moves with frightening speed.
Luckily, Hesperornis is much more agile.
But he's exhausted.
Which gives the mosasaur one last shot.
Hesperornis is a true survivor,
venturing further into the ocean than any dinosaur ever has.
But these waters are treacherous, even for the best swimmers.
Despite the dinosaurs' success in the shallows,
the mosasaurs
rule the waves.
Eight hundred miles north, on land,
it's a different story.
Fueled by a warm, stable climate,
the dinosaurs' dominance here is unrivaled.
The great sauropods are thriving among the tall trees,
as they have since the dawn of the Jurassic.
But down below, there has been a revolution.
A female hadrosaur.
While she may be dwarfed in present company,
she's actually larger than an elephant.
And she won't be held up by these giants,
because nothing can stop a mother on a mission.
And that mission
is to feed her family…
who are somewhere
down there.
Long ago, their cheek-stuffing ancestors were scarce and scattered.
But hadrosaurs are now so successful, their herds are thousands strong.
The greatest gatherings of dinosaurs the world has ever known.
But this female's family isn't traveling with the herd.
There, in the safety of the crèche,
a sprawling nursery for hundreds of young hadrosaurs…
…including her own.
At six months old, they have insatiable appetites,
and will eat almost anything she brings them.
Anything.
Feeding in this bird-like way takes a lot of refills,
so she's constantly leaving to go find food.
And when moms are away,
little ones will play.
With the wingspan of a fighter jet,
pterosaurs are now bigger than ever.
And crèches are the perfect hunting grounds,
where unguarded nests are the easiest pickings.
Despite the threat from this towering monster,
the mothers will defend their babies at all costs.
But the giant pterosaur is determined to feed.
The screams from the nest are like a dinner bell to the predator.
But the little ones aren't just crying in fear.
They're calling for help.
This fierce instinct to protect their young
is central to the hadrosaurs' remarkable success.
But other dinosaurs are taking defense to a whole new level
because the arms race between predator and prey is escalating.
And this will give rise to the most iconic dinosaurs of all time.
This will take so long
that the continent of North America will shift,
the land buckling up into the sky.
The Rocky Mountains.
It's here, in the foothills below,
that the dinosaurs are making an impact.
Pachycephalosaurus.
Using their outrageously thick skulls…
to duel for supremacy.
And alongside them,
a dinosaur with even more impressive headgear.
Triceratops.
She may look like a rhinoceros,
but she's twice the size of one.
And armed with spear-like horns over one meter in length.
Triceratops and Pachycephalosaurus have impressive weapons.
Yet there are some here
that are even more armed and dangerous.
Under the cover of darkness,
the latest and greatest of the armored warriors.
Six meters long and highly territorial.
Ankylosaurus magniventris.
He's on patrol for intruders
bold enough to breach his borders.
His tank-like torso is covered in dozens of thick, bony plates.
And what's more,
he has a powerful new weapon.
A club-like tail, weighing half a ton,
that he can use to take on whatever stalks these forests.
He senses something.
His borders have been breached…
by the worst possible intruder of all.
A Tyrannosaurus rex.
Ankylosaurus
versus T. rex.
An evolutionary stalemate,
millions of years in the making.
But in this arms race,
there's one thing that does set these dinosaurs apart.
Intelligence.
T. rex is one of the most fearsome predators of all time.
And to remain at the top of her game…
…she must eat the equivalent of 200 steaks every day.
And yet, so far, she hasn't eaten a single bite.
That's because she has special plans for this take-out meal.
But Ankylosaurus is no light snack.
Six tons of muscle and bone,
with an assortment of lumps and bumps.
Even for T. rex,
it's quite a drag.
Finally,
her journey's end.
And the reason she's gone to all this effort.
Five hungry hatchlings.
A ferocious killer,
yes.
But also,
a devoted mother.
She will ensure
her little ones are well-fed…
to give them the very best start in life.
Something their distant ancestors
could only dream of.
Far back in the Triassic, tiny Marasuchus hatched into hell.
These dinosaurs-in-the-making,
forced to live in the shadows.
Hiding from the ruling reptiles.
But when fate intervened…
they turned catastrophe
into opportunity…
and began their monumental rise.
Growing bigger, stronger, and ever more formidable.
In time,
they would triumph, not just on land,
but in the sea
and the sky.
After 160 million years,
the dinosaurs are now so dominant…
…nothing on Earth can stand in their way.
But something not of this Earth
will.
Because as this family's journey is just getting started,
another journey
is approaching its end.
The asteroid, now hurtling towards Earth at 50 times the speed of sound,
will finally have its date with destiny.
It smashes into the ocean off the coast of Mexico,
with the power of a billion atomic bombs.
Temperatures are hot enough to vaporize the seabed…
along with every living thing for hundreds of kilometers.
Far away, in the foothills of the Rockies,
these great dinosaurs have no idea what's about to hit them.
The largest earthquakes in history.
But the worst is yet to come.
An enormous wall of superheated debris explodes outward.
The dinosaurs caught beneath this death cloud
are entombed.
Their world is so hot, it literally bursts into flames.
Even the toughest armor
is no protection.
The cloud quickly engulfs the entire planet,
suffocating it with ash.
Shrouding it in darkness.
The few still standing at the end of the day
are in a nightmare.
Choking in the gloom.
By nightfall,
the death toll for the dinosaurs is catastrophic.
Starved of the sun's rays,
an impact winter descends on the Earth.
Global temperatures drop by 25 degrees Celsius.
Conditions too cold for almost any dinosaur to withstand.
Giant sauropods,
laid to rest
in the cinders of the very trees that made them so tall.
In their crowded colonies,
those who live together,
die together.
Protective mothers cannot shield their young
from the freezing temperatures.
The punishing cold has also taken its toll
on the most famous dinosaur of all.
The Tyrant King
has fallen.
Even the mighty Tyrannosaurus rex
will not survive this.
The reign of the dinosaurs
has finally
come to an end.
But 66 million years later…
the dinosaurs are rising again.
This time,
at our hands.
Today, their fossils stand as monuments to a lost world.
But more than that,
they are the keys that unlock the secrets of the dinosaur story.
Our understanding of their lives is now greater than ever.
From their very first moments,
to their very last.
And the revelation that on Earth's darkest day,
not all dinosaurs died.
Some were small enough to find shelter from the apocalypse.
And survive
even to this day.
The flying dinosaurs we now call the birds.
And the clues to their past are hiding in plain sight.
The remarkable journey that started 235 million years ago
continues alongside us.
They are the last remaining link…
to a long-lost kingdom
that was
the age
of the dinosaurs.