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.

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.

The documentary series gives a bird's-eye view of South America, as condors soar along the Andes, scarlet macaws explore the heart of the Amazon and hummingbirds and vultures see the continent's greatest sights. It is a journey that includes Machu Picchu, the Nasca Lines and the cities of Rio de Janeiro and Santiago. In Patagonia, giant petrels shadow killer whales as they hunt seals by stranding their huge bodies on the beach. At Iguassu Falls, dusky swifts dive through the cascades to huddle in communal roosts while hummingbirds bathe below. In a secret Andean location, condors soar in flocks over 40-strong and scavenge on casualties from herds of fighting guanacos. Elsewhere, a mother condor gently pushes her youngster to the edge of a 200-metre cliff, as flight school begins. Deep in the Amazon, macaws seek medicinal clay. They are joined by a host of secretive jungle animals, including spider monkeys and tapirs, all after the same remedy. In Peru, condors soar over fighting sea lions waiting for causalities and on a mass exodus north, birds converge on the Panama Canal. In Costa Rica, black vultures descend on turtles as they lay their eggs in the sand and pick off the eggs that ping-pong through the air.

On a vast plateau cradled in the heart of the rocky mountain range lies two million acres of unspoiled wilderness, never farmed and never fenced. Canyons, lakes, rivers and mountains, a refuge for magnificent animals and a spiritual sanctuary for generations of Americans, all resting on the largest super volcano in North America. This is Yellowstone, America's first national park, a raw and powerful beauty that truly comes to life through immersive 3D.

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.

Is it humankind's greatest achievement? 12 billion miles away a tiny spaceship is leaving our Solar System and entering the void of deep space. It is the first human-made object ever to do so. Slowly dying within its heart is a plutonium generator that will beat for perhaps another decade before the lights on Voyager finally go out. But this little craft will travel on for millions of years, carrying a Golden Record bearing recordings and images of life on Earth. In all likelihood Voyager will outlive humanity and all our creations. It could be the only thing to mark our existence. Perhaps some day an alien will find it and wonder. The story of Voyager is an epic of human achievement, personal drama and almost miraculous success. Launched 16 days apart in Autumn 1977, the twin Voyager space probes have defied all the odds, survived countless near misses and almost 40 years later continue to beam revolutionary information across unimaginable distances.