When you have a large rock in the middle of a delta on the edge of the ocean, what should you do with it? Turn it into a fortified castle of spectacular proportions! With a maximum height of 90 meters above sea level and a scant 44 population, there are more tourists than locals on any given day! Because it is connected by a tidal causeway (which was only made permanent/dry in 1879), it makes a spectacular picture, surrounded by ocean, when it is high tide, some 14m above the low tide water level.
With a rich history of refuge and strongholds, it was first used as a Gallo-Roman fortification in the 6th century. By the 8th century, when it was called Monte Tombe, it had a more monastic function, and by the 10th century, it was a strategic part of the Normandy defenses. The Romanesque church of the abbey was added in the 11th Century. With narrow streets winding up the hillsides, and an imposing appearance from the distance (and up close). It is an amazing place of living history.