Awe-inspiring fortress in the middle of the sea

Mont Saint Michel is a stunning castle located in Normandy, France. The most incredible aspect of the castle is its location - It stands on top of a small granite island only accessible during low tide. I had never seen anything like it! This castle dates back to the Middle Ages and is a spectacular example of medieval architecture. The castle was built on multiple levels with labyrinthine corridors, and small rooms everywhere. It was once used as a prison. Wandering through its halls and stairways was an adventure in itself. What captured my attention was how this place seemed to test human creativity with the natural laws of the ocean. The tides of the ocean are a sophisticated and complex system, and this fortress takes advantage of the tide-cycle to protect itself and all who live there. The fortress has survived for centuries because of the ingenuity and resourcefulness people that built it.