Durham Cathedral was the most daring structure of its age - the first structure of the modern age. With its astonishing grasp of engineering - thrust and counter-thrust - it was a century ahead of any other building in Britain.
Dan Cruickshank also reveals a building that is as puzzling as the pyramids but which, with the right key, he is determined will give up its ancient secrets. "Nothing is constructed by chance - every piece of the puzzle has a meaning - even the things that look like mistakes. Each has a secret message to impart", says Cruickshank.
Meanwhile monks' skulls reveal a luxury lifestyle, while records of tightrope walking and sexual incontinence cast an altogether different light on monastic life. And what is the explanation behind the cathedral's modern invention?
