The frozen poles are home to the planet's ultimate survivalists, including polar bears, penguins and Arctic wolves; their world is changing fast -- breaking apart under their feet -- and their resilience will be tested beyond the extreme.
How have some plants managed to live 5000 years? They are masters of photosynthesis and have survived on trips into space. In fact, there are now "plantimals". Perhaps it is time we learned more from plants about our world and how to live in it as partners.
This new age of discovery is revealing there is still so much to learn about the cat family. Using high-tech collars, Professor Alan Wilson has discovered it is not straight-line speed that is a cheetah's greatest weapon but their ability to break, change direction and accelerate. His research is rewriting what we understand about the fastest animal on land. This is also a crucial time for cat conservation - most are threatened, facing extreme habitat loss and conflict with humans. Yet there are many positive stories of cats bouncing back from the brink,
Siberia - It accounts for 10% of the land on our planet. Siberia is known for its frost and is known worldwide as one of the coldest places on earth. However, Siberia is home to numerous species of large wild animals, beasts and other creatures, including musk deer, camel, gazelle and rare species of lizard - Siberian salamander, which can be several years in a frozen state at - 40gradusov C and survive. From the cold north to the southern steppes - all Siberia, in all its splendor. Kamchatka - Land exploding volcanoes and glaciers, a country of ice and fire.
Marine invertebrates are some of the most bizarre and beautiful animals on the planet, and thrive in the toughest parts of the oceans. Divers swim into a shoal of predatory Humboldt squid as they emerge from the ocean depths to hunt in packs. When cuttlefish gather to mate, their bodies flash in stroboscopic colours. Time-lapse photography reveals thousands of starfish gathering under the Arctic ice to devour a seal carcass. A giant octopus commits suicide for her young. A camera follows her into a cave which she walls up, then she protects her eggs until she starves. The greatest living structures on earth, coral reefs, are created by tiny animals in some of the world's most inhospitable waters.
The first episode tells how invertebrates became the first creatures of any kind to colonise dry land. Their forerunners were shelled and segmented sea creatures that existed 400 million years ago. Some of them ventured out of the water to lay their eggs in safety, and Attenborough compares those first steps with today's mass spawning of horseshoe crabs off the Atlantic coast of North America.
Much of Australia consists of vast tracts of uninhabited land, a perfect hunting ground for the country's imperious birds of prey. From the brown falcons that feed on the country's deadliest snakes, to eagles that have been known to start fires on purpose so they can hunt fleeing animals, soar above the diverse habitats of this island continent in the company of its most accomplished aerial predators.