10. No Man’s Fort, UK
Built in the 19th century as a sea fort, this massive structure in the Solent off the coast of Portsmouth has been turned into a luxury hotel in the middle of the sea. With 22 rooms, a lighthouse, rooftop hot tubs, a laser tag arena, and even its nightclub, it feels like a floating fortress of fun.
Its isolated location and military past make it one of the most bizarre yet unforgettable places to stay.