Arctic adventures

Wonderful camera work and fascinating insights as David Attenborough examines how the arrival of winter, with temperatures down to -70°C, winds reaching 120mph and complete darkness, sparks a ruthless battle for survival.

As a blizzard rages, a female polar bear treks into the Arctic mountains to give birth, while the world's population of spectacled eider ducks (the ice must be a bugger for those glasses) braves the weather.