A hundred years ago there were one and a half billion people on Earth. Now, over six billion crowd our fragile planet Earth. But even so, there are still places barely touched by humanity. This series will take to the last wildernesses and show you the planet Earth and its wildlife as you have never seen them before.
Imagine our world without sun. Male Emperor penguins （帝企鹅） are facing the nearest that exists on planet Earth - winter in Antarctica. It's continuously dark and temperatures drop to minus seventy degrees centigrade. The penguins stay when all other creatures have fled because each guards a treasure: a single egg rested on the top of its feet and kept warm beneath the downy bulge of its stomach. There is no food and no water for them, and they will not see the sun again for four months. Surely no greater ordeal is faced by any animal. As the sun departs from the Antarctic it lightens the skies in the far north. It's March and light returns to the high Arctic, sweeping away four months of darkness.