It was the bloodiest war in history, yet Hitler's brutal invasion of the Soviet Union and Stalin's subsequent fight back is surprisingly little known in the West. More than 30 million people died during Hitler and Stalin's terrible war in the East - more than in any other single war in history. With direct testimony from people who perpetrated atrocities and the victims who suffered on both sides, we bring the unspeakable to the screen and allowing victims and aggressors to tell the truth as they see it. In the first episode, we will look at Hitler's plans to invade the Soviet Union and the horror of the first months of conflict.

An unsettling yet visually fascinating documentary presenting the history of nuclear weapons development and testing between 1945 until 1963. Narrated by William Shatner, features extremely rare film segments from top secret government archives and startling footage of nuclear bomb tests conducted by Great Britain and China, plus the largest atomic explosion ever created by Russia, and de-classified U.S. footage released to the public as recent as May, 2006. Whether being exploded under the ocean, suspended by a balloon, shot from a cannon or even detonated in space, these weapons are capable of devastating destruction - the quality of these images is as startling as are remarkable.

The extraordinary wildlife, culture and history of this immense, fascinating ocean and its myriad islands are revealed in stunning detail. With its coral reefs, turquoise lagoons and dramatic oceanic atolls, the South Pacific is the archetypal paradise. It is still relatively healthy and teeming with fish, but it is a fragile paradise. International fishing fleets are taking a serious toll on the sharks, albatross and tuna, and there are other insidious threats to these bountiful seas. We look at what is being done to preserve the ocean and its wildlife.

Professor Brian Cox examines how it was that in a universe made of stars, rocks and endless space, a conscious civilisation was born. His latest adventure takes him from a submerged space station in Star City on the outskirts of Moscow, to Ethiopia, high above in the Great Rift Valley, where he encounters the geladas, mankind's distant ancestors. Despite once being Africa's most successful primate, a species who at one time roamed across the entire continent, these days they are found in one just place in the remote Ethiopian Highlands. Cox investigates why these ancestors retreated, yet modern mankind has expanded across the planet.

Today, the topic of climate change is a major part of daily life, yet 40 years ago it was virtually unheard of. Since then, Horizon have followed scientists as they have tried to unpick how the climate works and whether it is changing. Dr Helen Czerski delves into this unique archive to chart the transformation of a little-known theory into one of the greatest scientific undertakings in history. It has been a constantly surprising journey of discovery that has revolutionised our understanding of climate, and seen scientists face unprecedented controversy and criticism.

During 1942, the Red Army moved from defeat to victory.