Mont Saint Michel, I had never heard of it before and then I was there. An amazing abbey in a tidal basin near the English channel. Do a search and check it out, better yet go there sometime. The monastery was started in 709AD and grew into this huge abbey, monastery and later a prison on top of a big rock with a town below. Stone masonry was the occupation of centuries perhaps more force labor than volunteer labor. An impregnable stronghold during the Hundred Years War, Mont-Saint-Michel is also an example of military architecture. Its ramparts and fortifications resisted all the English assaults and as a result the Mount became a symbol of French national identity. The abbey is a confluence of stairways, large rooms, suspended passageways, large support pillars and an enormous wheel and pulley used to hoist building materials and later provisions. The building is an example of architectural mastery perching storied buildings on a steep slope.