MORGAN FREEMAN, NARRATOR: There are few places harder to get to in this world. But there aren't any where it's harder to live. The average temperature here at the bottom of the Earth is a balmy 58 degrees below. That's when the sun is out.
It wasn't always like this. Antarctica used to be a tropical place densely forested and teeming with life. But then the continent started to drift south. And by the time it was done drifting, the dense forests had all been replaced with a new ground cover, Ice.
As for the former inhabitants, they had all died or moved on long ago. Well, almost all of them.
Legend has it that one tribe stayed behind. Perhaps they thought the change in weather was only temporary. Or maybe they were just stubborn.
But whatever their reasons, these stalwart souls refused to leave.
For millions of years they have made their home on the darkest, driest, windiest and coldest continent on Earth. And they've done so pretty much alone. So in some ways this is a story of survival. A tale of life over death. But it's more than that, really.
This is a story about love.
Like most love stories, it begins with an act of utter foolishness.
The emperor penguin is technically a bird although one that makes his home in the sea. So if you're wondering what he's doing up here on the ice, well, that's part of our story.
Each year at around the same time he will leave the comfort of his ocean home and embark on a remarkable journey. He will travel a great distance, and though he is a bird, he won't fly. Though he lives in the sea, he won't swim. Mostly, he will walk. But he won't walk alone.
It is March. Summer is over. And another long polar winter is about to begin.
The birds have been feeding in the ocean waters for three months. Now, their bellies full it is time to find a mate.
Their breeding ground can be up to 70 miles away. To get there they will walk day and night continuously, sometimes for a week. It is a long, dangerous and seemingly impossible journey, and some of them will not survive it.
Nonetheless, when the last of the clan has finally clamored onto the ice their long march will begin just as it has for thousands of years.
The destination is always the same. Their path, however, is not. The ice on which the birds travel never stops shifting and changing. New roadblocks will appear to baffle them every year.
We're not exactly sure how they find their way. Perhaps they were assisted by the sun or the stars, or maybe having taken this march for thousands of generations they are guided by some invisible compass within them.
They never stay stumped for long. Eventually, one of them will pick up the trail, and the journey continues.
When they get tired of walking, they'll give their feet a rest. They'll use their bellies instead.
Theirs is usually a graceful parade, but not always.
Each day the temperature drops a little further, and the sun will set earlier.
The weather becomes noticeably harsher almost by the hour.
By now similar caravans are approaching from every direction.
And finally, often on the same day even around the same time they will arrive at the place where each and every one of them was born. Here they will mate in relative safety. They are now far from the water's edge where most predators lurk. And the large ice walls will offer some protection from the harshest winds.
But the real reason they have chosen this place lies beneath their feet. The ice is thicker here. It will stay solid until summer keeping their young from accidentally falling through into the freezing ocean.
And so, having arrived they begin to pursue their journey's purpose, finding a mate.
We don't really know what they're looking for in a partner. We only know that they are, in fact, looking. We also know when they've found what they're looking for.
Emperor penguins are monogamous, sort of. They mate with only one partner per year, which means every new season, all bets are off.
Because there are fewer males than females here hostilities among the ladies are inevitable. A taken male instantly becomes an unavailable male. So occasionally, a female will attempt to interrupt a courtship. The men don't seem to mind. They just wait for the fight to end and take the opportunity to preen. They're not that different from us, really. They pout. They bellow. They strut. And occasionally, they will engage in some contact sports.
FREEMAN: Within a few weeks, one way or the other, most of the animals have found the one they are looking for.
For the next eight months these two will participate in an ancient and complicated affair. There will be tenderness. There will be separation. There will be reunion. And if their partnership is successful, there will be new life.
For now, they wait for the egg and for the brutal winter, which will do everything in its power to destroy that egg.
By May the light will nearly have disappeared from the sky and the temperature continues to drop.
And for those who began their march too late or have fallen behind because of weakness or hunger hope of survival is now remote.
The lone penguin has no chance against the winter's cold. He will simply fade away, absorbed by the great whiteness all around him.
FREEMAN: As winter descends, the tribe's only defense against the freezing cold is the group itself. It is almost as if they create another organism altogether.
The huddled animals form a single moving mass, one designed for the sole purpose of sustaining warmth.
Winter's first storm is upon them.
Within a few weeks, days begin to pass with virtually no light at all. Moons come and go in the soon-to-be-endless night. And finally, one day in early June we remember why they came here.
As soon as the egg appears, it is instantly hidden from the cold. The tiny beating heart within the shell cannot survive much more than a moment's exposure to the freezing air.
From now on, the couple has but a single goal, keeping their egg alive.
The hungry mother must return at once to the sea to eat. But before she leaves, she must entrust the egg to its father.
Some, young couples perhaps, are too impulsive or rushed. And within moments, their affair comes to an end.
They can only watch as the ice claims their egg and the life within it. This couple's partnership is now over. The long march in vain. With no reason to stay they will wander back to the sea.
Other couples have lost their egg as well. As for the others their partnership is about to change.
With unending patience the pair rehearses the steps they will need to transfer the egg from the mother to the father. They practice this clumsy ballet dozens of times if need be. And then, with great care they will dance it.
And now begins one of nature's most incredible and endearing role reversals. It is the penguin male who will tend the couple's single egg. While the mother feeds and gathers food to bring back for the newborn, it is the father who will shield the egg from the violent winds and cold.
He will make a nest for the egg atop his own claws keeping it safe and warm beneath a flap of skin on his belly. And he will do this for more than two months.
Having passed the egg, the exhausted female must depart quickly. She must eat soon or she will die.
As the winter progresses, the father will be severely tested. The mother will be tested as well.
Her return trip to the sea is considerably more difficult than the original march to the nesting ground. It is colder now. And she will have lost almost a third of her body weight producing the egg. She is literally starving. Of course, the fathers are nearly starving, too. But for them, a meal is far off in the distance.
By the time their vigil atop the egg is over, the penguin fathers will have gone without food of any kind for over 125 days. And they will have endured one of the most violent and deadly winters on Earth, all for the chick.
FREEMAN: As the fathers settle into their long wait at the breeding ground, the winter's second storm arrives. The temperature is now 80 degrees below zero. That's without taking into account the wind which can blow 100 miles an hour.
Though they can be aggressive during the rest of the year, at this time the males are totally docile. A united and cooperative team, they brace against the storm by merging their thousand bodies into a single mass. They will take turns, each of them getting to spend some time near the center of their huddle where it's warmer.
As they move about, the fathers will balance their eggs like tightrope walkers.
The exhausted mothers have marched 70 miles. They are now back where they started three months ago. But they aren't anywhere near the water's edge.
New ice is formed along the shore forcing them to walk several more miles before they reach the sea. Food is actually only a few inches below them, but they have no way of getting to it here.
To survive, they must reach the new ice edge or find some other opening. Sometimes this search will last for days.
Naturally, after their long walk, they are eager to get back in the water -- sometimes a little too eager.
They can hold their breath for over 15 minutes and dive to a depth of 1,700 feet approaching the sea floor itself to feed on fish, krill and squid.
They will also skim along the ice just below the ocean's surface searching for any fish that may have lodged there.
While the mothers finally fill their empty bellies, the fathers cling to life on the surface trying to keep the eggs safe and warm. The wind will occasionally bring snow to quench the males' thirst.
They have been without food now for over three months. Each day brings them closer to exhaustion and starvation. Eventually some, usually the older ones, will simply fall asleep and disappear.
FREEMAN: Now it is dark almost all the time. And the mother of all blizzards is about to arrive.
The fathers now make an extra effort to weld their bodies together and resist the winter's rage.
Above them, the southern lights dance virtually around the clock. For now, there is almost only night. The hungry mothers aren't the only ones overjoyed by their return to the sea. Their predators, unfortunately, are happy to have them back as well.
With a snap of its jaws, the leopard seal actually takes two lives. That of the trapped mother and that of her unborn chick who will never be fed.
By July the females know it is time to return to their nest. And so, for the third time this year, the mothers take the long walk. Only this time they walk in the dark.
FREEMAN: The ravenous and freezing night lingers, seemingly without end, until, finally, the darkness begins its slow retreat.
After many months, life returns in earnest to the South Pole, but only momentarily. And, yet, it is enough. Their victory over winter has begun. Their efforts have not been in vain.
Though the light is returning, the winter is far from over. And the worst is actually yet to come.
No matter how cold it is or how hungry they are, the fathers must keep moving. If they don't, they will die, but then -- each day, more eggs will hatch. But this chick is hungry. He needs the food in his mother's belly.
But his father is hungry, too. He hasn't eaten in nearly four months now. If his mate doesn't arrive soon, he will be forced to abandon his child and return to the sea to feed himself. He will have no choice.
But there is one secret weapon against his newborn's hunger. The father coughs up a milky substance. Despite his own hunger, this tiny meal has been relegated to a small crease in his throat just for this moment. This little banquet will keep the chick alive for a day, perhaps two, hopefully long enough for the mother to arrive.
For some, it is already too late.
The mothers step up their rhythm, as if sensing the urgency.
They shuffle along as quickly as possible, hauling their overstuffed bellies one last mile. And then, at last, they're back.
To find each other in the enormous crowd, the penguins must rely on sound, not sight. As they circle, the returning mothers trumpet loudly and wait for their mates to call back. The sound is deafening, and yet, somehow, each of them will hear their mate's song.
The couple has found one another. The mother sees her chick for the first time. And, at last, the family is together.
And just as they did with the egg, the parents now quickly pass off the newborn from one to the other. Now it is the mother's turn to protect her chick from the fierce cold. The father and his check sing to one another, making sure each knows the other's voice. It is the only way the two will find each other when the father returns.
As the chick enjoys his first real meal, the father prepares to sever the bond between them. It's not easy to do. The fathers have gone without food for over four months. They will have lost as much as half their weight. But, still, they must walk for over 70 miles.
This leg of the journey may be why there are fewer males than females. Each year, some of these new fathers will not make it back to the sea.
FREEMAN: Like the sun, the chicks grow stronger every day, but they are not yet ready to leave their mothers.
In time, after being perched atop their mother's feet for 1,000 paces, like a child learning to dance on her mother's shoes, the chick takes his first steps alone.
With the wind's return, the temperature drops. This year, winter's going out with a bang. This is the first storm for the new chicks, and many of them will not survive it.
When the winds stop, the search for lost chicks begins. Some have kept warm by huddling together. Others have not been so lucky. The loss is unbearable. Every year, some bereft mother will respond to her agony in an unimaginable way. Having lost her own chick, she will attempt to steal another's. But the group will not allow it.
Back in its mother's care, the chick is not eager to leave again. Despite having known each other only a few days, the bond between mother and child is surprisingly strong. In the next few weeks, it will only grow stronger.
FREEMAN: Winter's grip slowly weakens and the chicks begin to run free.
Some need a little encouragement, but eventually they all find their way.
Winter may have ended but the dangers have not.
It is late August now.
And time for the mothers to return and feed once more.
For some this development is unacceptable, but it is also non- negotiable.
Because they are old enough now the chicks are left alone for the first time.
As spring arrives the ice packs near the ocean's edge begin to melt shortening the distance between the sea and the breeding ground.
It isn't long before the fathers return their bellies heavy with food.
The chicks will gather at once to meet them and sound their calls.
The returning fathers will circle the excited newborns and listen until he hears his chick's call.
Some will never find their chick.
The newborn will have died from cold or hunger or at the hands of some predator.
But for those that do find their young the reunion is a joyful one.
And, very quickly, the young chick's belly will be full again.
For the next several months, the parents will take turns shuttling back and forth to the sea for food.
And occasionally the new family can actually spend some time together.
By September the ice has begun to thin and crack.
The sea gets closer, allowing the parents to go back and forth more frequently.
The chicks' new coat of feathers is now thick and full enough to protect them on their own.
And by November the ocean is within a few hundred yards of the breeding ground.
As the ice melts the brand-new family prepares to go their separate ways.
The couples, locked for the past nine months in their ancient ritual of coming and going, will now part for the last time.
And as their newest members look on, the tribe returns to their home, at last.
For the next three months they will lavish in the rich and warmish waters of their short summer.
They will feed and they will play.
And in all likelihood their chicks will never see them again.
They will remain here alone and unsupervised for a few more weeks growing stronger.
The ice continues to melt returning the borrowed water to the sea, and beckoning the young penguins into the ocean as well.
It is now December and they are ready to leave the place where they were born.
And although they have never known the ocean nor touched it they, like their parents, are of the sea.
And so one day they'll take the plunge and go home for the first time.
For four years, the chicks will live at sea.
But as the sunlight begins to disappear at the end of their fifth year and the warm days begin to cool, they, too, will climb out of the water.
And they will march just as they have done for centuries ever since the emperor penguin decided to stay to live and love in the harshest place on Earth.