Centuries ago, the Romans built a temple on a hill in Normandy, France, a few miles from the English Channel. Later, monks replaced the temple with a chapel.
Then, in the year 725, an earthquake struck the area, and the waters of the English Channel surged inland, covering the farmland that surrounded the hill. The hill became an island, called Mont Saint Michel.
Today, Mont Saint Michel is still an island, sometimes. At high tide, the village of Mont Saint Michel sits on a steeply sloped island, surrounded by walls built in the Middle Ages, with the chapel at the top of the slope.
But at low tide, the waters around the island recede, and Mont Saint Michel is connected to the shore by a half-mile of swampy beach. During these times, visitors can walk to Mont Saint Michel without touching water. But if they’re not quick enough, and the tide comes in, they could find themselves swimming to Mont Saint Michel instead!
In 1875, a causeway was built connecting Mont Saint Michel with the mainland of France, so that the island could be reached on foot in high tide too.