Tidal island Benedictine abbey off the Normandy coast, founded in the 8th century. Inscribed 1979.
From Wikipedia
The Mont-Saint-Michel Bay is located between Brittany and the Normandy peninsula of Cotentin. The bay was listed as a UNESCO world heritage site in 1979 for its aesthetic quality and its importance to the Christian tradition. Due to the significant tidal movements in this region a large part of the bay is uncovered at low tide. There are two granitic islands in the bay: Tombelaine and the Mont-Saint-Michel. Many birds and harbor seals live in this area.