The video is ten years old, but it's the first time I've seen this uncommonly clear an explanation of some of the techniques used 1,000 years ago by mere mortals to construct immense buildings dedicated to unprovable religious teachings.
BBC Four: How to Build a Cathedral
The great cathedrals were the wonders of the medieval world - the tallest buildings since the pyramids and the showpieces of medieval Christianity. Yet they were built at a time when most of us lived in hovels. Architectural historian Jon Cannon explores who were the people that built them and how were they able to achieve such a bold vision.