Now that's the Mont-Saint-Michel, in Normandy, France. It is wonderful. The land surrounding Mont-Saint-Michel is so even, that when the tide goes in, it is said to go as fast as a horse running. It is not true, but the tide rises at 8-10 km/h, which is still quite impressive to see with your own eyes. You have to run if you don't want the tide to catch up on you. I live near it !