The Mont Saint-Michel Bay is located between Brittany and the Normandy peninsula of Cotentin . The bay is part of the club of the world's most beautiful bays and is listed as a UNESCO world heritage site. 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 seal live in this area.