The series is a re-examination of some of the under-reported and darkest parts of American modern history using little known documents and newly uncovered archival material, looking beyond official versions of events to the deeper causes and implications and exploring how events from the past still have resonant themes for the present day. This episode addresses the historical backround, consequences and reasons behind the use of atomic bombs against the Japanese in the second world war.

Dr Michael Mosley traces the sinister ways the experimental psychology has used to try to control our minds. He finds that the pursuit of mind control has led to some truly horrific experiments and left many casualties in its wake. Extraordinary archive captures what happened - scientists systematically change the behaviour of children; law abiding citizens give fatal electric shocks; a gay man has electrodes implanted in his head in an attempt to turn his sexuality. Michael takes a hallucinogenic drug as part of a controlled experiment to try to understand how its mind-bending properties can change the brain. This is a scientific journey goes to the very heart of what we hold most dear - our free will, and our ability to control our own destiny.

Follow actor William Shatner through interviews with the other actors who have portrayed starship Enterprise captains in five other incarnations of the Star Trek franchise. Shatner's subjects discuss their lives and careers before, during and after their tenure with Star Trek. With the use of conversations and archival footage, they explore the pressures, stigmas and sacrifices that accompanied their roles and their larger careers. During the process of the film and with help from the other Captains, Sir Patrick Stewart, Avery Brooks, Kate Mulgrew, Scott Bakula and Chris Pine, Shatner overcomes his disdain and learns to embrace his best known character, Captain James T. Kirk.

August 6th 1945 marked the start of a terrifying new episode in human history. This documentary marks the 70th anniversary of the day when the world's first atomic bomb was dropped on the Japanese city of Hiroshima by a Boeing B-29 USAF Superfortress bomber, nicknamed Enola Gay after the pilot's mother". Up to 80,000 people - 30 per cent of the population - were killed by the blast and resulting firestorm and over 70,000 were injured. This documentary gives a minute-by-minute account of what happened on that fateful day, through the testimony of people who were there and rarely-seen archive footage from the time. Made on location in Hiroshima and the USA, it features unique interviews with eyewitnesses who have seldom, if ever, spoken about the experience. Several of them are no longer alive, they include the last surviving member of the crew of the Enola Gay - navigator Dutch Van Kirk who died in July 2014.

Dr Thomas Dixon delves into the BBC's archive to explore the troubled relationship between religion and science. From the creationists of America to the physicists of the Large Hadron Collider, he traces the expansion of scientific knowledge and asks whether there is still room for God in the modern world. He looks at what happens when new scientific discoveries start to explain events that were once seen as the workings of God, and explains how some of our most famous scientists have seen God in the grandest laws of the universe. Finally, he finds intriguing evidence from brain science which hints that belief in God is here to stay.

Dr Janina Ramirez embarks on a journey through six decades of the BBC archives to create a television history of one of the most celebrated figures in art - Leonardo Da Vinci. Ramirez shows how experts and art presenters have turned to television to bring Leonardo's artwork out of galleries and into our living rooms. Through television they have explored the origins of Leonardo's boundless curiosity, his pioneering use of light and shade, and his remarkable scientific exploration.
Along the way Dr Ramirez discovers Britain's little-known version of The Last Supper, the gruesome ways Leonardo acquired his anatomical knowledge - and even what lies beneath the Mona Lisa.