Fancisco Pizarro hoped to find great riches in the land of the Inca when he set off on his third voyage to the new world in 1527. Travel back in time with Michael Wood and learn how Pizarro ransomed the life of a king for a room full of gold and silver. Trough letter and drawings from the 16th century and film from modern-day south America, discover this remarkable story of greed, faith, dishonor and valor.

In the fourth episode, Morgan Freeman examines how different faiths see the creation of the world, taking him on a journey to the Vatican, Cairo and the jungles of Guatemala.

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.".

Diarmaid MacCulloch's own life story makes him a symbol of a distinctive feature about Western Christianity - scepticism, a tendency to doubt which has transformed both Western culture and Christianity. In the final programme in the series, he asks where that change came from. He challenges the simplistic notion that faith in Christianity has steadily ebbed away before the relentless advance of science, reason and progress, and shows instead how the tide of faith perversely flows back in. Despite the attacks of Newton, Voltaire, the French Revolutionaries and Darwin, Christianity has shown a remarkable resilience. The greatest damage to Christianity was actually inflicted to its moral credibility by the two great wars of the 20th century and by its entanglement with Fascism and Nazism. And yet it is during crisis that the Church has rediscovered deep and enduring truths about itself, which may even be a clue to its future.

In the fourth episode of the series, Clovis was the first Frankish king to acknowledge the Christian faith. This changed the direction of Europe's history.

Memory is the glue that binds our mental lives. Without it, we’d be prisoners of the present, unable to use the lessons of the past to change our future. From our first kiss to where we put our keys, memory represents who we are and how we learn and navigate the world. But how does it work? Neuroscientists using cutting-edge techniques are exploring the precise molecular mechanisms of memory". By studying a range of individuals ranging —from an 11-year-old whiz-kid who remembers every detail of his life to a woman who had memories implanted— scientists have uncovered a provocative idea. For much of human history, memory has been seen as a tape recorder that faithfully registers information and replays intact. But now, researchers are discovering that memory is far more malleable, always being written and rewritten, not just by us but by others. We are discovering the precise mechanisms that can explain and even control our memories. The question is— are we ready?