In 2014, the International Space Station had to move three times to avoid lethal chunks of space debris and there is an increasing problem of satellites mysteriously breaking down. With first-hand accounts from astronauts and experts, know the scale of the problem of space junk. Our planet is surrounded by hundreds of millions of pieces of junk moving at 17,000 miles per hour. Now the US government is investing a billion dollars to track them, and companies around the world are developing ways to clear up their mess - from robot arms to nets and harpoons. Learn the science behind the hit film Gravity and discovers the reality is far more worrying than the Hollywood fiction.

In this final episode we complete our journey, travelling back from the March equinox to the end of June. Kate Humble is in the Arctic at a place where spring arrives with a bang, whilst Helen Czerski chases a tornado to show how the earth's angle of tilt creates the most extreme weather on earth.

Follow three professional gamers from around the world as they compete for a million dollar prize in the first Dota 2 International Tournament. In recent years, E Sports has surged in popularity to become one of the most widely-practiced forms of competitive sport today. A million dollar tournament changed the landscape of the gaming world and for those elite players at the top of their craft, nothing would ever be the same again

A stunning documentary about the escalating global nuclear arms crisis, Countdown to Zero is a fascinating and frightening exploration of the dangers of nuclear weapons, exposing a variety of present day threats and featuring insights from a host of international statesmen and experts. Among the voices are President Jimmy Carter, Mikhail Gorbachev, Pervez Musharraf, Tony Blair, former CIA Operations Officer Valerie Plame Wilson, the Ploughshares Fund’s Joe Cirincione and Stanford political scientist Scott Sagan. traces the history of the atomic bomb from its origins to the present state of global affairs: nine nations possessing nuclear weapons capabilities and others racing to join them, with the world held in a delicate balance that could be shattered by an act of terrorism, failed diplomacy, or a simple accident. It makes a compelling case for worldwide nuclear disarmament, an issue more topical than ever with President Obama and other world leaders working to revive this goal today. Written and directed by Lucy Walker, Countdown to Zero was screened for attendees of this year’s Global Zero International Conference in Paris and the TED Conference in Long Beach, California.

It's a timeless classic of children's literature and the third most-quoted book in English after the Bible and Shakespeare. But what lies behind the extraordinary appeal of Alice's Adventures in Wonderland to generations of adults and children alike? To mark the 150th anniversary of its publication, this documentary explores the life and imagination of the man who wrote it, the Reverend Charles Dodgson, better known as Lewis Carroll." Broadcaster and journalist Martha Kearney delves into the biographies of both Carroll himself and of the young girl, Alice Liddell, who inspired his most famous creation. Kearney's lifelong passion for Carroll's work began as a young girl, when she starred as Carroll's heroine Alice in her local village play. She discusses the book with a range of experts, biographers and distinguished cultural figures - from the actor Richard E Grant to children's author Philip Pullman - and explores with them the mystery of how a retiring, buttoned-up and meticulous mathematics don, who spent almost his entire life within the cloistered confines of Christ Church Oxford, was able to capture the world of childhood in such a captivating way

'Blood Brothers' follows the lives of two species, Paranthropus boisei and Homo habilis who embody two alternative ways of ape-man life. Although heavyset, with distinctive gorilla-like faces, the boisei are gentle characters. They live within a strict social structure and are led by a dominant male whose strength and power holds the group together. The habilis have taken a different approach to survival. They don't have the specialisms of the boisei but instead have developed into the archetypal jack-of-all-trades, inquisitive scavengers prepared to try almost anything to survive. Tough, active, gregarious and noisy, they are always on the move and always alert to the possibility of a meal. But in the near drought of the dry season the habilis are struggling. It seems as if their way of life cannot help them when conditions are tough.