Travelers need especially deep pockets in three cities boasting the costliest hotel stays in the world: Geneva, Dubai, and Kuwait City, according to a World Hotel Index compiled by Bloomberg. In Geneva, the average cost for a hotel night is $308, followed by Dubai at $273, Kuwait City at $253, and Zurich at $250. In the U.S., Miami (fifth on the list) is the costliest place for lodging, at $245 a night; New York is No. 10, at $233 a night, while San Francisco, 17th on the list, averages $211 a night.