Photo: Canterbury Cathedral

The tread-wheel crane inside the central tower at Canterbury Cathedral.

Photo: Canterbury Cathedral

Looking west at the entrance to the north side aisle at Canterbury Cathedral.

Photo: Canterbury Cathedral

West transept arch looking into the nave at Canterbury Cathedral.

Photo: Canterbury Cathedral

The vault inside the central ("Bell Harry") tower at Canterbury Cathedral.

Photo: Canterbury Cathedral

Canterbury Cathedral colonnade, taken from triforium level.

Video: Building the Great Cathedrals

Building the Great Cathedrals from Providence Pictures on Vimeo.

Building The Great Cathedrals

PBS Airdate: October 19, 2010

These skyscrapers of stone dominated skylines for nearly a thousand years. Now, a team of scholars and builders investigates how they went up, and why some of the tallest fell down. Embedded in stone and stained glass, they uncover a hidden mathematical code—ripped from pages of the Bible—that was used as a blueprint to build the great Gothic Cathedrals.