14. Tel Aviv, Israel
I have a lot of energy, and I don't need much sleep. That's the way to approach Tel Aviv, where there is little time for such. This is probably the least well-known and most underrated "24-hour city" in the world, accurately nicknamed "The City That Never Stops." Coffee, booze, food, wild nightlife, and cool parties -- there's always something going down in one of Tel Aviv's distinct neighborhoods; and not only on weekends, mind you. Sure, Tel Aviv might sound manic, but actually, it's far from it. Expect a relaxed feeling, beautiful people, and a nifty sense of coolness, not to mention, a seemingly never-ending beach! A nice added bonus thrown in for free.