10. Mont Saint-Michel
Probably the most dramatic structure in Europe, Mont Saint-Michel is much like a town in itself. Located on an island in Normandy, the peculiarity of this castle is that it is not so readily accessible unless the tide agrees with the visitors. It’s one of the oldest constructions of the sort as it was built in the 8th century.
Since it is part of the UNESCO list of World Heritage Sites, it goes without saying that it is, without a doubt, a must-see destination. Plus, there’s virtually no chance of you being unimpressed with the fact that the castle is surrounded by water, which came in handy when attackers tried to conquer it as they would have drowned.