In this bird's-eye view of two continents, demoiselle cranes negotiate a dangerous Himalayan pass on their way to India while high-flying bar-headed geese take the fast track five miles above. In Rajasthan, vultures watch hunting tigers hoping for a meal and pigeons visit a temple dedicated solely to sacred rats. Pigeons are also our guide to the greatest gatherings of camels on Earth and learn to dodge buzzards around the battlements of Jodhpur Fort. 9,000 cranes overwinter in the most unlikely of spots - a barbed wire compound in the centre of a desert town. In Australia, rainbow lorikeets drop in on Sydney and patrol Australia's Gold Coast. In the outback, white cockatoos swirl in thousands and budgerigars pass Uluru (Ayers Rock) and gather in the biggest flocks ever recorded. In China, swallows and swifts visit the Great Wall and the Forbidden City of Beijing. In Japan, the country's most revered birds - Japanese cranes are fed fish by appreciative locals and are joined in strange, momentary harmony by hungry red foxes, white-tailed eagles and Steller's eagles. As peace descends, Japanese cranes dance beautifully in the snow.

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.

Scientists around the world are asking themselves the same questions. Over the decades the focus on dolphin research has changed from asking 'how intelligent are dolphins?' to 'how are dolphins intelligent?' and we look at research from the world's foremost dolphin experts for the answers.

Commander Stephen Hawking and his space ship the SS Hawking encounter an alien A.I., then race to the edge of the universe, and plunge into an alternate Earth. It's an epic quest to discover the secret of the universe: The Theory of Everything. RIP. Stephen Hawking.

Do dolphins think the way we do or are their brains wired in a very different way from ours? Will we communicate with them one day? Dolphins have been a source of curiosity to humans and have appeared in our stories and myths for thousands of years. What is the link between our two species? Why do we seem to be so interested and curious about each other?