It is potentially one of the greatest archaeological discoveries in the history of Christianity, the ruins of one of the oldest monasteries in Europe. Here, under the location where the altar once stood, scientists have dug up an exquisite marble box holding what they believe to be the bones of John the Baptist, the man who baptized Jesus. If the date of the bones lines up with the Bible's profile of John, could it finally solve the mystery of what happened to his remains after his beheading, 2,000 years ago?