Take your diving gear along to reach an underwater hotel; stay in a disused US Air Force radar tower in the heart of the equatorial rainforest; slide back the roof of your bedroom to gaze at the stars; sleep in the cabin of a dockside crane that you can rotate, or in chalets hidden in the forest, a survival pod from an oil rig platform, a giant shoe, a coffin, lighthouse, tree, plane, train, chapel, prison, igloo, or even a red cube lost in the countryside... All these strikingly unusual hotels have grown up around the world in the last decade or so. So that you'll never get bored and spoil your holiday, we've taken great pleasure in tracking down and testing some exceptional places to stay that are really out of the ordinary. With prices ranging from 20 euros to over 1,000 euros per night, we've selected 50 hotels in 23 different countries.