Graced with vaulted roofs and soaring windows, Europe’s cathedrals were built without the benefit of modern materials or load-bearing technologies. How do these massive structures sustain their open floor plans? Combining insights from experts such as Oxford University’s Jacques Heyman with computer modeling and location and laboratory footage, this program addresses the mechanics of the arch. Chartres and Ely Cathedrals serve as subjects for a discussion of vector equilibrium, lines of thrust, planes of action, buttresses, flying buttresses, and pinnacles. The dome of St. Peter’s Basilica and the Beauvais Cathedral are also examined. Produced by the Open University. (30 minutes)