An aerial view as a high tide submerges a narrow causeway leading to the Mont Saint-Michel, on France's northern coast, Saturday, March 21, 2015. A supertide has turned France's famed Mont Saint-Michel into an island and then retreated out of sight, delighting thousands of visitors who came to see the rare phenomenon. The so-called "tide of the century" actually happens every 18 years (AP Photo) FRANCE OUT, APTOPIX