Penguins as they have never been seen before. From the freezing Antarctic to the scorching tropics, 50 spy cameras capture unique footage of three extraordinary species.
Emperor penguins cross a treacherous frozen sea to reach their breeding grounds, and on the way one becomes lost in a blizzard. Once there, the females flipper flight over the males and those that succeed waddle-walk with their partners. They must lay their eggs without touching the ice, but it is the males that face the greatest challenge - overwintering alone in the coldest place on earth.
Rockhoppers brave the world's stormiest seas, only to come ashore and face a daunting assault up a 300-foot cliff, hopping most of the way up. Having laid their eggs, these plucky birds face airborne attacks from skuas and vultures.
Humboldts are a strange tropical penguin that have rarely been filmed. To reach their desert nests they negotiate 20,000 predatory sea lions, dodge vampire bats and battle half a million sharp-beaked seabirds.
The hard work for all the penguins finally pays off when their tiny, vulnerable chicks begin to hatch.
Among the spy cameras capturing unique behaviour is a technological first - robotic penguins with cameras for eyes.