In 966, a group of Benedictine monks founded a church there, with the extraordinary Gothic-style abbey perched on the pinnacle of the island following in 1023.
Over the years the monument has served many functions—a fortress during the Hundred Years' War between England and France, it was a prison during the French Revolution when it was known as the "Bastille of the seas".
Bursting with tourists
Mont Saint-Michel and its bay have been listed as a UNESCO World Heritage site since 1979.
While it has long been a popular place of pilgrimage, it has also become a tourist mecca, packed with souvenir shops, restaurants and hotels.
In 2022, the island attracted nearly 2.8 million visitors, with some 36,000 cramming into an area covering under 4 square kilometres on one day alone (August 18).
When cut off by the sea, the citadel looks to be afloat but that breathtaking spectacle was lost for over a century after a road linking the island to the mainland was built on a raised dyke in the 1870s.
The silt that built up around the road held back the tide, preventing the island from being cut off.
Between 2005-2015, around 230 million euros was spent on returning the site to the sea, including flushing out excessive sand and silt and replacing the road with a wooden footbridge.
The tides in the bay of Mont Saint-Michel are among the highest in the world and create shifting sands that are notoriously tricky to navigate.
In 2022, tightrope walker Nathan Paulin trialled a new approach when he walked 2,200 metres along a wire suspended 114 metres above the bay, breaking the record for longest tightrope walk.
An inseparable part of Mont Saint-Michel lore is La Mere Poulard (Mother Poulard) the inn founded by Anne Boutiaut, who devised a huge popular omelette soufflee that is still part and parcel of the tourist experience over a century later.
Ernest Hemingway, Coco Chanel, Margaret Thatcher and Leon Trotsky are just some of the characters to have enjoyed its hospitality.