Summer is the season of plenty for most animals, but not polar bears. Unable to hunt seals until the sea freezes over again, they grow hungrier by the day. For other animals summer is when youngsters must learn how to survive.
Welcome to an extreme landscape of rock, ice and snow. We tour the mightiest mountain ranges, starting with the birth of a mountain at one of the lowest places on Earth and ending at the summit of Everest. Find out how some of the most secretive animals rise to the challenge of mountain life. Share one of Earth's rarest phenomena, a lava lake that has been erupting for over 100 years. The same forces built the Simian Mountains where we find troops of gelada baboons nearly a thousand strong. In the Rockies, grizzlies build winter dens inside avalanche-prone slopes and climb the peaks to devour abundant summer moths. In another world first, the programme brings us astounding images of a snow leopard hunting on the Pakistan peaks.
Across our planet, there are a handful of places that truly astonish, like Mount Everest, the Grand Canyon and Victoria Falls. These wonders seem to have little in common other than - literally - taking your breath away. But they share one other thing: they pose extraordinary challenges for their inhabitants. The second of two documentaries profiling some of the world's most expansive - and inhospitable - landscapes, and the people who live there. A fisherman in Zambia faces off against crocodiles and risks being swept to his death as he tries to make a living above the imposing Victoria Falls, and in the Amazon, a giant fish offers salvation to a hungry family that calls the river home. A boy's future hangs on the outcome of a single horse race in the vast grasslands of the Steppe, and in a European salt marsh, a young man duels with a savage bull in a centuries-old battle of wills.
The Nsefu lion pride of Zambia are in an enviable position, with a litter of new cubs, control of the best territory on the Luangwa River, and strong males to protect them. But as the cubs grow older, pressure mounts as they begin to understand their roles and how every misstep can threaten the very existence of their family.
The highest mountain range on earth is home to extraordinary animals and remarkable ancient cultures. In the depths of winter, snow leopards creep into isolated mountain villages in search of food. In hidden valleys, bizarre-looking monkeys huddle for warmth in a frozen forest. Ancient Buddhist monasteries have age-old rituals creating beautiful works of art made from mountain sand and athletes compete in the gruelling Everest marathon. Strange and exotic creatures live in the Himalaya - the chiru, with the warmest wool in the world, snakes bathing in hot springs and wild yak competing in their annual rut. Breathtaking photography reveals a lost world of surprises in the latest landmark wildlife series from the BBC.
In the vast South Atlantic, huge pods of dolphins, massive penguin colonies and the largest gathering of marine mammals on earth pack chains of extraordinary islands, created by powerful volcanic forces far below them. Nutrient-rich upwellings create profusions of life in some areas, whilst extreme isolation and abyssal depths host a world of bizarre creatures in others.