Go with us behind the scenes at CERN to follow one of the most epic and expensive scientific quests of all time: the search for the Higgs particle, believed to give mass to everything in our universe. However, the hunt for Higgs is part of a much grander search for how the universe works. It promises to help answer questions like why we exist and is a vital part of a Grand Unified Theory of nature". At the heart of the pursuit of the elusive particle is the same feature that makes snowflakes beautiful and human faces attractive: the simple and enchanting idea of symmetry. Presenter Jim Al-Khalil

The key to understanding the universe seems to be understanding its smallest components. But the quantum realm bears little resemblance to the universe we know. Image a particle that can be many places at the same time and communicate changes instantly across vast distances, even to the other side of the Universe. Shrinking down billions of times, into the realm of atoms and sub-atomic particles, takes us into a bizarre world of paradoxes and multiverses. Explore with us quantum physics and the potential applications in computer science.

The filmmakers challenge former Indonesian death-squad leaders to reenact their mass-killings in whichever cinematic genres they wish, including classic Hollywood crime scenarios and lavish musical numbers. Anwar Congo and his friends have been dancing their way through musical numbers, twisting arms in film noir gangster scenes, and galloping across prairies as yodeling cowboys. Their foray into filmmaking is being celebrated in the media and debated on television, even though Anwar Congo and his friends are mass murderers.
Medan, Indonesia. When the government of Indonesia was overthrown by the military in 1965, Anwar and his friends were promoted from small-time gangsters who sold movie theatre tickets on the black market to death squad leaders. They helped the army kill more than one million alleged communists, ethnic Chinese, and intellectuals in less than a year. As the executioner for the most notorious death squad in his city, Anwar himself killed hundreds of people with his own hands.
The Act of Killing is about killers who have won, and the sort of society they have built. Unlike ageing Nazis or Rwandan génocidaires, Anwar and his friends have not been forced by history to admit they participated in crimes against humanity. Instead, they have written their own triumphant history, becoming role models for millions of young paramilitaries. The Act of Killing is a journey into the memories and imaginations of the perpetrators, offering insight into the minds of mass killers. And The Act of Killing is a nightmarish vision of a frighteningly banal culture of impunity in which killers can joke about crimes against humanity on television chat shows, and celebrate moral disaster with the ease and grace of a soft shoe dance number.

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.

Einstein's world-shaking Theory of Relativity says that time travel is perfectly possible -- if you're going forward in time. Finding a way to travel backwards requires breaking the speed of light, which so far seems impossible. But now, strange-but-true phenomena such as quantum nonlocality (where particles instantly teleport across vast distances) may give us a way to make the dream of traveling back and forth through time a reality. Step into a time machine and rewrite history, bring loved ones back to life, control our destinies. But if succeed, what are the consequences of such freedom? Will we get trapped in a plethora of paradoxes and multiple universes that will destroy the fabric of the universe?

What is the universe made of? If you answered stars, planets, gas and dust, you'd be dead wrong. Thirty years ago, scientists first realized that some unknown dark substance was affecting the way galaxies moved. Today, they think there must be five times our understanding of the universe and the nature of reality itself has drastically changed over the last 100 years - and it's on the verge of another seismic shift. In a 17-mile-long tunnel buried 570 feet beneath the Franco-Swiss border, the world's largest and most powerful atom smasher, the Large Hadron Collider, is powering up. Its goal is nothing less than recreating the first instants of creation, when the universe was unimaginably hot and long-extinct forms of matter sizzled and cooled into stars, planets, and ultimately, us. These incredibly small and exotic particles hold the keys to the greatest mysteries of the universe. What we find could validate our long-held theories about how the world works and what we are made of -- or, all of our notions about the essence of what is real will fall apart.