The remarkable stories of some of the extraordinary people who make their homes in the Arctic, the harshest environment on Earth.

The Arctic is the harshest environment on Earth - little food grows, it's dark for months on end and temperatures stay well below freezing for much of the year. Yet four million people manage to survive here. This film tells the remarkable stories of extraordinary people who make their homes in nature's deep freeze.

In springtime, Amos and Karl-Frederik set out across the sea ice with their dogs to catch a real-life sea monster - a Greenland shark. Inuit mussel-gatherers venture underneath the sea ice at low tide for a perilous race against time as they gather their food.

The children of Churchill, Manitoba, set out on the most dangerous trick or treating Halloween in the world, risking coming face-to-face with deadly polar bears on the streets of their town. Who will get the tastiest snack?