Particle physicist Prof. Brian Cox asks, 'What time is it?' It's a simple question and it sounds like it has a simple answer. But do we really know what it is that we're asking? Brian visits the ancient Mayan pyramids in Mexico where the Maya built temples to time. He finds out that a day is never 24 hours and meets Earth's very own Director of Time. He journeys to the beginning of time, and goes beyond within the realms of string theory, and explores the very limit of time. He discovers that we not only travel through time at the speed of light, but the experience we feel as the passing of time could be an illusion.

Six videos the Rolling Stones have selected from their files. Including Mick and Keith interviews where they explain why this particular selection.

Operation Condor was a campaign of political repression and terror involving intelligence operations and assassination of opponents, officially implemented in 1975 by the right-wing dictatorships of the Southern Cone of South America. The program was intended to eradicate communist or Soviet influence and ideas, and to suppress active or potential opposition movements against the participating governments.

Can we find the Garden of Eden? Bible scholar Dr Francesca Stavrakopoulou thinks so. In the final episode of her series re-examining conventional readings of the Bible, she argues that the Garden of Eden has nothing to do with the origins of humanity, but is rather a story concealing dramatic events about a particular figure in a particular place, two and half thousand years ago. Marshalling compelling evidence from archaeology, Islam and the Bible text itself, she identifies and visits the exact site of Eden. It's a revolutionary theory which challenges some of the most cherished preconceptions about Eden in both Christianity and western culture.

From stars, galaxies and moons to subatomic particles, black holes and invisible phenomena, discover the most bizarre, mysterious and exotic things in our universe

Every year, around the world, seasonal changes transform entire landscapes and draw in millions of creatures as these great events unfold. This fantastic series combines the epic scale of Planet Earth and the intimate, emotional stories of charismatic animals as they struggle to survive. Using state of the art technology, these programmes capture the Earth's most dramatic and epic wildlife spectacles and the intimate stories of the animals caught up in them.
The Great Melt: The summer melt of Arctic ice, opening up nearly three million square miles of ocean and land, provides opportunities for millions of animals, including beluga whales, families of Arctic foxes, vast colonies of seabirds, and the fabled Arctic unicorn, the narwhal. For polar bears, however, it is the toughest time of year. Why? How will they survive? A mother polar bear and her cub make their first journey together onto the sea ice. They are looking for ringed seals, their favourite prey. It is a serious business but the cub just wants to play. The melting ice makes it harder for them to hunt and threatens their survival. In a unique aerial sequence, the migration of narwhal with their distinctive unicorn-like tusks is filmed for the first time. The whales' journey is risky as they travel along giant cracks in the ice. If the ice were to close above them, they would drown. Hundreds of beluga whales gather in the river shallows. They rub themselves on smooth pebbles in one of the most bizarre summer spectacles. Guillemot chicks take their first flights from precipitous sea cliff nests to the sea 300 metres below. They attempt to glide to safety but many miss their target. Their loss is a bonus for the hungry Arctic fox family waiting below. As the melt comes to an end the bears gather, waiting for the sea to freeze again. Two 400kg males square up to each other to spar.