2,500 years ago, the ancient Greek philosophers expressed doubts about the supernatural. However, when Christianity succeeded in taking over the Roman Empire, it also closed down the great Greek schools of philosophy and ushered in what became known as the Dark Ages. Jonathan Miller visits the absent Twin Towers to consider the religious implications of 9/11 and meets Arthur Miller and the philosopher Colin McGinn. He searches for evidence of the first ‘unbelievers’ in Ancient Greece and examines some of the modern theories around why people have always tended to believe in mythology and magic.