Each year, a quarter of our planet is frozen solid, so let's journey to these ice kingdoms:
Dive under the ice ceiling and learn to swim with the seal pups, take to the skies with frozen flamingos, and settle in for a snooze with a windy walrus.
Watch orcas sneak up on bowhead whales while they're relaxing in the spa, meet a Greenland shark that is easily 250 years old, and witness the polar bears who are finding their food closer and closer to humans.
Hold your breath in the frozen forest where wolves play hide-and-seek with bison, and meet the lemmings that outwit an arctic fox by building their home right under her feet, buried deep beneath the snow.
Wrap up warm, and discover spine-tingling true stories from our incredible planet, in this ground-breaking new BBC Earth series narrated by Sir David Attenborough.