We move around in space, but we are stuck in a prison of time moving ever forwards. Einstein said, 'The distinction between past, present and future is only a stubbornly persistent illusion.' Is our experience of the ticking clock merely a trick of the mind? Could science ever make the clock move backwards? Experiments in quantum physics are showing that the future influences the present: what happens later limits the choices we think we have now. The laws of physics say visiting or talking to ourselves in the past is possible – but changing history once we get there is not.

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.

The BBC's definitive television history of the rise and fall of the Nazis. The Nazis - A Warning From History exposes the popular myths surrounding the rise and fall of the Third Reich. The series explores how the Nazis came to power, how they ruled, how they treated their occupied territories and, above all, how a cultured nation could be responsible for such acts of inhumanity. How could a political party as fundamentally evil and overtly racist as the Nazis come to power? This remains one of the most enigmatic questions of the last century. Acclaimed historian Laurence Rees examines what led a cultured nation at the heart of Europe to commit the atrocities it did. In so doing, he exposes popular myths and encourages understanding of the real forces that led to one of the darkest chapters in modern history. Was it simply the hypnotic power of Hitler's rhetoric? Did the Gestapo really impose themselves by terror on an unwilling population? Through interviews with witnesses and perpetrators, along with archive film and records, this six-part series unveils a more chilling reality.

In this episode he traces India in the days of the Roman Empire. In Kerala the spice trade opened India to the world, whilst gold and silk bazaars in the ancient city of Madurai were a delight for visiting Greek traders. From the deserts of Turkmenistan Michael travels down the Khyber Pass to Pakistan to discover a forgotten Indian Empire that opened up the Silk Route and at Peshawar built a lost Wonder of the World.

Dr Michael Mosley seeks to establish the truth about meat. Every year, humans raise and eat 65 billion animals - nine animals for every person on the globe. In this eye-opening documentary, Michael examines the impact that this is having on the planet and finds out what meat eco-friendly carnivores should be buying. Is it better to buy free-range organic or factory-farmed meat? The answers are far from obvious.

One man's journey to discover the bitter truth about sugar. Damon Gameau embarks on a unique experiment to document the effects of a high sugar diet on a healthy body, consuming only foods that are commonly perceived as 'healthy'. Through this entertaining and informative journey, Damon highlights some of the issues that plague the sugar industry, and where sugar lurks on supermarket shelves. This will change the way you think about healthy food.