"Today's abbey is built on the remains of a Romanesque church, which was built on the ruins of a Carolingian church. Visiting the abbey, imagine the headaches and hassles the monks had when they built it. They ferried granite from across the bay and hiked it uphill." Rick Steves
The island in the background was the quarry for the abbey. As the abbey grew the other island shrunk.
France, Mont St Michel
FranceMont St. Michel