Naturalists Charlie Russell and Maureen Enns film recently discovered grizzlies on Siberia's Kamchatka peninsula.

The highest mountain range in the world, the Himalayan range is far reaching, spanning thousands of miles, and holds within it an exceptionally diverse ecology. Coniferous and subtropical forests, wetlands, and montane grasslands are as much a part of this world as the inhospitable, frozen mountaintops that tower above. The word Himalaya is Sanskrit for abode of snow, fitting for a stretch of land that houses the world’s largest non polar ice masses. Extensive glacial networks feed Asia's major rivers including the Ganges, Indus, and Brahmaputra. More than a billion people rely on these glacier-fed water sources for drinking water and agriculture. The Himalayas are not only a remarkable expanse of natural beauty. They're also crucial for our survival.

This astounding documentary delves into the mysteries of the Tunguska event – one of the largest cosmic disasters in the history of civilisation. At 7.15 am, on 30th June 1908, a giant fireball, as bright the sun, exploded in the sky over Tunguska in central Siberia. Its force was equivalent to twenty million tonnes of TNT, and a thousand times greater than that of the atomic bomb dropped on Hiroshima in 1945. An estimated sixty million trees were felled over an area of over two thousand square kilometres - an area over half the size of Rhode Island. If the explosion had occurred over London or Paris, hundreds of thousands of people would have been killed.

A scientist explains how the savagery and efficiency of the insect world could result in their taking over the world.

Most of us think of death as something clear-cut, and that medical science has it neatly figured out. This feature documentary explodes such assumptions through its exploration of a phenomenon that blurs life and death to an unprecedented degree. In what Tibetan Buddhists call tukdam, advanced meditators die in a consciously controlled manner. Though dead according to our biomedical standards, they often stay sitting upright in meditation; remarkably, their bodies remain fresh and lifelike, without signs of decay for days, sometimes weeks after clinical death. Following ground-breaking scientific research into tukdam and taking us into intimate death stories of Tibetan meditators, the film juxtaposes scientific and Tibetan perspectives as it tries to unravel the mystery of tukdam.

A journey into four classical elements through the four main characters of the film. The main characters in the movie represent each of their own elements.

In this retrospective tribute, acclaimed filmmaker Jean Walkinshaw hails the 100th anniversary of Mount Rainier National Park in Washington by talking to those who know it best: the scientists, naturalists, mountain climbers and artists whose lives have been touched by the peak's far-reaching shadow. The result is a harmonious blend of archival material and high-definition footage celebrating an icon of the Pacific Northwest.

Author Helen Macdonald follows Britain’s greatest river over four seasons, encountering salmon, beavers and the microscopic creatures helping to answer science's biggest questions.

Described as being a film about determination, danger and the ocean’s greatest depths, James Cameron's "Deepsea Challenge 3D" tells the story of Cameron’s journey to fulfill his boyhood dream of becoming an explorer. The movie offers a unique insight into Cameron's world as he makes that dream reality – and makes history – by becoming the first person to travel solo to the deepest point on the planet.

With a combination of wild observations and specially designed tests, this film will guide us through the latest research on bird intelligence, a journey which will re-define the meaning of ‘bird-brained’.

Carefully picked scenes of nature and civilization are viewed at high speed using time-lapse cinematography in an effort to demonstrate the history of various regions.

Steve Backshall visits a hedgehog rescue centre in Surrey founded by Brian May. He meets the dedicated staff and discovering the stories behind some of the animals being treated, helps to release a successfully treated hedgehog back into the wild, and offers advice on how to make a garden into a welcoming environment for the creatures.

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The Rastreadoras de El Fuerte are a group of mothers of disappeared persons in northern Sinaloa who, in the absence of the authorities, twice a week go out with picks and shovels in search of the remains of their children; a testimony of the abandonment of the State, the aggressions of the drug traffickers, the indifference of society and the pain, but also of the strength and courage that keep these women together, and of their empowerment to mobilize society in community organization.

Lost Worlds looks at untouched aspects of nature in parts of the world where humans rarely tread. From plants, to animals, to geology, this artfully photographed documentary presents facets of the biological world that you are not likely to see anywhere else.

An astonishing journey revealing the awesome power of the natural world. Over the course of one single day, we track the sun from the highest mountains to the remotest islands to exotic jungles.

Near the cold Pyrenees of Iberia, surrounded by ancient and dark green forests, lies a strange land where the rain is scarce and the wind is always blowing. The soil is poor, there are no trees and the landscape resembles the moon. Is this what the future of desertification will look like? Incredible creatures with surprising behavior live in this strange landscape. The documentary explores a place with very dry skin but a wet hidden heart where even waterfowl or amphibians can live. Living in such conditions is not easy and only the toughest animals will survive.

William Shatner sits down with scientists, innovators and celebrities to discuss how the optimism of 'Star Trek' influenced multiple generations.

In GHOSTS OF THE FOREST daredevil bird and wildlife cinematographer, John Young is embarking on a journey into the rainforest of the tropical north to find those creatures often heard but rarely, if ever, seen.

One of only two living mammals to lay eggs, the platypus has baffled and inspired the scientific community for hundreds of years. Three years in the making, this stunning natural history film takes us down the East Coast of Australia to the many serenely beautiful habitats of the platypus. Technology specially created for this film captures images from inside the nesting chamber of a wild platypus, and records the extraordinary sounds of the mother suckling her offspring. We watch as they grow from newborns to adulthood. Join renowned documentary makers David Parer and Elizabeth Parer-Cook (Dragons of Galapagos, Wolves of the Sea) on this fascinating journey from the rainforests of Queensland to the frozen mountains of Tasmania, as they reveal new insights into this mysterious creature.