Key lime pie, anyone? Beaches, margaritas and relaxed vibes are all part of visiting the island city of Key West, where summer never ends. World-class diving and snorkeling opportunities abound here, and when they're not in the water, tourists find Cuban food and visit the historical homes of Harry S. Truman and Ernest Hemingway. Key West is a popular cruise ship stop, but drivers can also access it via the scenic Overseas Highway. Be sure to stand at the Southernmost Point of the Continental United States, marked by a painted buoy.