Dubai is building the world's first luxury underwater hotel called Hydropolis:
"Hydropolis is not a project; it's a passion," enthuses Joachim Hauser, the developer and designer of the hotel. His futuristic vision is about to take shape 20m below the surface of the Arabian Gulf, just off the Jumeirah Beach coastline in Dubai. The £300 million, 220-suite hotel is due to open at the end of 2007 and will incorporate a host of innovations that will take it far beyond the original blueprint for an underwater complex worthy of Jules Verne.
Link - via Shurebit