16. Las Vegas
With restaurants by nearly all the country's celebrated chefs, pool and spa amenities at five-star hotels, and scads of nightly live entertainment options, Sin City has far more to offer than gambling. (Though if you do want to casino hop, take advantage of the monorails, trams, and air-conditioned connector walkways to avoid the sizzling Strip temperatures.) A helicopter tour to the Hoover Dam makes for a scenic side trip as well.