Nature's Great Migrations

A thousand elephants, from magnificent bulls to vulnerable orphans, come together in a crucial annual gathering in northern Kenya while facing deadly threats from both predators and poachers.

As they undertake the world's longest land migration, 100,000 caribou face starving bears and wolves, deadly frozen rivers and rugged mountains in the arctic wilderness of Canada and Alaska.

Thousands of zebra face lions, hunting dogs, drought and starvation as they brave one of Botswana's most-brutal wildernesses and make Africa's longest land migration to reach the rich grasslands of Nxai Pan National Park.