If you're looking for a really cool place to stay, you can't go wrong with an ice hotel. These are temporary structures made up entirely of snow and ice, which attract visitors interested in novelty and unusual environments. The first and most famous ice hotel was built in Sweden, but there are now several other ice hotels in Scandinavia as well as in Canada and Romania. Visitors eat from plates carved from ice, drink from ice glasses and sleep on ice beds lined in deer furs which keep them cosy through the night.

If you hate the cold, but don't mind getting wet, then why not try diving beneath the ocean for an underwater hotel experience. There is currently only one underwater hotel in existence - the Jules's Undersea Lodge in Florida, which is more of a working research station with rooms to rent, rather than a fully fledged hotel. Scuba certification is mandatory and the front door is 21 feet underwater. However, the world's first luxury underwater hotel is being built in Dubai, which will offer guests who do not dive - or even swim - the chance to sleep with the fishes, in this extravagant project that began construction in 2005.

Getting cold or wet is not to everyone's taste, and if you're looking for a stay that is out of this world, then you may soon be able to look down on earth from your hotel room. Genesis 1, the first step in the construction of a habitable complex in Space, was successfully launched into orbit in 2006 and is the start of the Bigelow Aerospace mission to build an affordable human space complex that will be accessible by the commercial section by 2015. Not only would a space hotel offer guests incredible views of the Earth and the Moon, it would also offer the endless entertainment of living in zero gravity.

Of course, it may be many decades before space travel is cheap enough for any typical person to afford, so if the ice has melted, you can't scuba dive or you just want to keep your feet planted firmly on Planet Earth, you can still enjoy a wholly unique experience at some of the world's top hotels. Swap the novelty factor of ice hotels and underwater abodes for a touch of opulence with a stay in a luxury , London, for example, and you're sure to enjoy a memorable experience that really is out of this world!