Idolized in ancient Norse mythology as the protector god, Thor battles evil ogres and a giant serpent bent on destroying mankind. It's the quintessential fight for survival that culminates in a final showdown between good and evil. But was the rise and fall of the hero Thor ancient code for something greater? Today, new discoveries unlock the hidden truth behind the Norse god of Thunder. Able to wield thunder from his hammer, Thor was the most revered of the Norse gods, from fending humanity from the giants that brought calamity, to his pursuit of the Midgard Serpent. Though, his fate is told to sealed during Ragnarok, it is actually the invasion of Christianity that proves far more damning to this mighty god.

In the fourth episode, Professor Marcus du Sautoy concludes his investigation into the history of mathematics with a look at some of the great unsolved problems that confronted mathematicians in the 20th century. After exploring Georg Cantor's work on infinity and Henri Poincare's work on chaos theory, he sees how mathematics was itself thrown into chaos by the discoveries of Kurt Godel and Paul Cohen, before completing his journey by considering some unsolved problems of maths today, including the Riemann Hypothesis.

Chaos theory has a bad name, conjuring up images of unpredictable weather, economic crashes and science gone wrong. But there is a fascinating and hidden side to Chaos, one that scientists are only now beginning to understand. It turns out that chaos theory answers a question that mankind has asked for millennia - how did we get here? In this documentary, Professor Jim Al-Khalili sets out to uncover one of the great mysteries of science - how does a universe that starts off as dust end up with intelligent life? How does order emerge from disorder? It's a mindbending, counterintuitive and for many people a deeply troubling idea. But Professor Al-Khalili reveals the science behind much of beauty and structure in the natural world and discovers that far from it being magic or an act of God, it is in fact an intrinsic part of the laws of physics. Amazingly, it turns out that the mathematics of chaos can explain how and why the universe creates exquisite order and pattern. And the best thing is that one doesn't need to be a scientist to understand it. The natural world is full of awe-inspiring examples of the way nature transforms simplicity into complexity. From trees to clouds to humans - after watching this film you'll never be able to look at the world in the same way again.

From director Amy Berg: 'Just a year and a half ago, after spending over four years on the same story for CNN and CBS before that, a paedophile priest named Oliver O'Grady decided he would participate in the film I wanted to make. It became Deliver Us From Evil -- the story from inside the sickest mind possible, the secrets that were meant to stay in the private files and crypts of the Roman Catholic Church, and the blind trust in those they perceived as God's messengers that left families with no faith and children with no innocence. After filming for a week and a half, the then defrocked priest mentioned he might need to move to Canada after this film comes public. Seeing the pain, corruption and missed opportunities to provide ministry to those in need was truly a tragic story to watch and the loss was more devastating than I ever imagined. It was so difficult to be so close to such a horror story that in the priest's words "never should have happened.".

There are some who believe that Darwin's theory of evolution has weakened religion. Conor Cunningham argues that nothing could be further from the truth.He travels to the Middle East where he shows that from the very outset, Christianity warned against literal readings of the biblical story of creation. In Britain, he reveals that, at the time, Darwin's theory of evolution was welcomed by the Anglican and Catholic Churches. Instead, he argues that the conflict between Darwin and God was manufactured by American creationists in the 20th century for reasons that had very little to do with science and religion and a great deal to do with politics and morality. Finally, he comes face to face with some of the most eminent evolutionary biologists, geneticists and philosophers of our time to examine whether the very

brilliant mathematicians whose genius has profoundly affected us, but which tragically drove them insane and eventually led to them all committing suicide. Kurt Gödel, the introverted confidant of Einstein, proved that there would always be problems which were outside human logic. His life ended in a sanatorium where he starved himself to death. Finally, Alan Turing, the great Bletchley Park code breaker, father of computer science and homosexual, died trying to prove that some things are fundamentally unprovable.