It's big and it's beautiful. It's got polar bears, wolves, whales, seals, foxes, albatrosses, the aurora and ice bergs the size of New York skyscrapers.
This is the world of the planet's two poles. An exploration, "Frozen Planet," starts this Sunday on the Discovery Channel, as the third installment in the BBC Earth series.
Firefly has published a companion book, by "Frozen Planet" executive producer Alastair Fothergill and Vanessa Berlowitz, who produced some of the episodes.
"No part of planet Earth is more hostile to life than the snow-and ice-covered regions thattlie around its two poles," writes naturalist and broadcaster Sir David Attenborough in the foreword. "Yet animals of many kinds -- land-living mammals in the north, birds in the south and sea mammals in both places - have over many thousands of years evolved extraordinary ways of surviving there."