E1-01-The Frozen Sea 北冰洋

The Arctic Circle, a frozen ocean ringed by three continents.

Survival here is a constant battle against the planet's most ferocious elements.

One third of the Arctic Ocean is covered in ice all year round and for half a year the sun does not rise above the horizon.

But in summer, the sun never sets.

Thousands of animals head north to reap their field as the shallow seas of the Arctic Circle become some of the richest on earth.

In winter, the Arctic Ocean is almost completely covered in ice.

The sea ice grows to encase the northern tips of Asia, Europe, North America, and several islands.

This is one of the most hostile habitats on earth, but the planet's most resilient animals survive above and below the ice.

Thousands of whales migrate across the Arctic Ocean to search food.

Seals nurse their young and compete for females.