The big blue is the world's greatest wilderness, far from shore and many kilometres deep. It's a vast marine desert where there is little to eat and nowhere to hide. Yet it's home to some of the biggest and most spectacular creatures on earth. This episode reveals what it takes to survive in this savage and forbidding world. We witness feats of incredible endurance, moments of high drama and extraordinary acts of heart-wrenching self-sacrifice. Every animal in the big blue must find their own unique way to survive. Sperm whales have the largest brains in the world. They live for 80 years, and we are only now beginning to learn the extraordinary complexity of their language of clicks - thought to coordinate the whole family in everything from childcare to hunting. With special pressure-proof cameras, we witness record-breaking feats of endurance as they hunt for squid a kilometre down into the abyss. Only recently have we begun to solve the mystery of where baby turtles disappear to in their early years. They leave the crowded waters of the coast and head to the open ocean, where they use floating debris like logs as life rafts. Here they remain until adulthood, adrift on the high seas in relative safety away from coastal predators. Over half of all animals in the open ocean drift in currents. Jellyfish cross entire oceans feeding on whatever happens to tangle with their tentacles. The jelly-like Portuguese man-of-war can harness sail power to fish with its deadly tentacles. Sometimes there is a brief explosion of food in this marine desert, but ocean hunters must be fast to make the best of this bonanza. We witness super pods of up to 5,000 spinner dolphins racing to herd vast shoals of lanternfish, briefly caught at the surface where it is thought they spawn. New aerial footage reveals, for the first time, the truth to a centuries-old sailors' legend of the 'boiling seas' - the spectacular feeding frenzy of 90kg tuna and dolphins smashing through the lantern fish shoals turning the sea white with foam.

A remarkable 200-million-year-old fossil - the bones of an ichthyosaur, a giant sea dragon - has been discovered on the Jurassic coast of Britain. David Attenborough joins the hunt to bring this ancient creature's story to life. Using state-of-the-art imaging technology and CGI, the team reconstruct the skeleton and create the most detailed animation of an ichthyosaur ever made. Along the way, the team stumble into a 200-million-year-old murder mystery - and only painstaking forensic investigation can unravel the story of this extraordinary creature's fate.

The film explores George Mallory's obsession with becoming the first person to reach the highest place on Earth. Told through the explorer's poignant and evocative letters to his wife, Ruth, previously unseen photos and film archive from 1924 (restored from the original nitrate especially for the film), dramatization and a modern-day expedition retracing the original route taken in 1924, Mallory's incredible adventure lives again. The expedition was led by renowned mountaineer Conrad Anker, whose life became inextricably linked with Mallory after he found Mallory s body on Everest in 1999. Using replica 1920s-era clothing and equipment, Anker sets out to solve the great mystery of whether Mallory succeeded in summiting Everest before he died he was last seen just 800 feet from the summit before the clouds closed in and he disappeared into legend. The most heart-breaking clue: All of Mallory's belongings were found intact on his body, except the photograph of his beloved Ruth, which he promised to leave at the top of the world if he succeeded.

Embark on a thrilling journey through time and five continents to the heart of creativity. Fusing social history, politics, science, nature, archaeology and religion, this international landmark series unravels a universal mystery - why the world around us looks like it does. Modern-day mysteries are answered by journeying back to the beginning of civilisation via some of the most amazing man-made creations in the world. In the first episode, one image dominates our contemporary world above all others: the human body. How Art Made the World travels from the modern world of advertising to the temples of classical Greece and the tombs of ancient Egypt to solve the mystery of why humans surround themselves with images of the body that are so unrealistic.

Richard Feynman is one of the most iconic, influential and inspiring scientists of the 20th century. He helped design the atomic bomb, solved the mystery of the Challenger Shuttle catastrophe and won a Nobel Prize. 25 years after his death - in his own words and those of his friends and family - this is the story of the most captivating communicator in the history of science.

No planet beats Saturn for jaw-dropping beauty. Saturn is the most photogenic planet in all the solar system. Some of the pictures are to die for. But the postcards only tell part of the story. It really is rolling and seething inside. For ringside action, soar above the planet with its six-sided storms. Even more mystery surrounds the impressive Fountains of Enceladus where the secrets of life might spring from the moons salty geysers. And the samples are coming out in space, there's a big sign there: Free Samples: Take One.