From lush cloud forests to bare summits that take your breath away, the higher you climb the tougher life gets on a mountain. Human Planet explores the extraordinary ways in which people survive at extreme altitudes where nature becomes utterly unforgiving. In the Altai Mountains in Western Mongolia the vast open spaces make hunting for animals almost impossible, so the locals have forged an astonishing partnership with golden eagles which can do the hunting for them. On the precipitous cliffs of the Simien Mountains of Ethiopia we join a young boy locked in a dramatic battle with fearsome gelada monkeys which are hell-bent on raiding his family's meagre grain harvest. In the Himalayan state of Nepal - the roof of the world - we witness a rarely seen ceremony: a sky burial. In a land where there is little wood to burn for cremation, and where burying the dead is virtually impossible, the dead are fed to vultures in the ultimate reverence of nature.

Dark energy - the mysterious force that is unexpectedly causing the universe's expansion to speed up. The effects of dark energy were discovered in 1998 but physicists still don't know what it is. Worse, its very existence calls into question Albert Einstein's general theory of relativity - the cornerstone of modern physics. The hunt for the identity of dark energy is on". Experiments on earth and in space generate data that might provide a clue, but there are also hopes that another Einstein might emerge - someone who can write a new theory explaining the mystery of the dark energy.

There's a killer lurking in our galaxy, a star ready to explode into a supernova. Seen from Earth, a supernova in the Milky Wave would have a terrible beauty. But for us, it could be fatal. In a few seconds, it can release as much energy as the sun will over its entire lifetime. It could be anywhere. It is nearly impossible to predict where and when the next supernova will happen. The hunt is on to find the next supernova before it finds us.

The next great voyage of human exploration has already begun: the search for life on planets orbiting distant stars. With extraordinary CGI, the world's most inspiring scientists, via extreme environments on Earth and around the solar system, the film takes viewers aboard the next generation of space ships, across the cosmos and beneath the clouds of the exo-planets to discover The Living Universe.
Part 1: 'The Planet Hunters' For as long as we’ve had eyes to see and minds to wonder we’ve marveled at the stars. Since the discovery of the first so-called exoplanet in 1994, the Planet Hunters have transformed the way we see the universe. It is the year 2157, and spacecraft Artemis enters the final phase of construction.

In the last episode, Al-Khalili turns detective, hunting for clues that show how the scientific revolution that took place in the 16th and 17th centuries in Europe had its roots in the earlier world of medieval Islam. He travels across Iran, Syria and Egypt to discover the huge astronomical advances made by Islamic scholars through their obsession with accurate measurement and coherent and rigorous mathematics.He then visits Italy to see how those Islamic ideas permeated into the west and ultimately helped shape the works of the great European astronomer Copernicus, and investigates why science in the Islamic world appeared to go into decline after the 16th and 17th centuries, only for it to re-emerge in the present day. Al-Khalili ends his journey in the Royan Institute in the Iranian capital Tehran, looking at how science is now regarded in the Islamic world

Horizon discovers what your cat really gets up to when it leaves the cat flap. In a groundbreaking experiment, 50 cats from a village in Surrey are tagged with GPS collars and their every movement is recorded, day and night, as they hunt in our backyards and patrol the garden fences and hedgerows. Cats are fitted with specially developed cat-cams which reveal their unique view of our world. You may think you understand your pet, but their secret life is more surprising than we thought.