Mackinac Island, Mich. (Pop.: 600)

While a horse-drawn carriage ride may seem like a romantic novelty to some, for the 600 residents of Lake Huron's Mackinac Island, it's a way of life. The 3.8-square-mile tourist destination had the foresight to ban all motorized vehicles back in 1898, and today only allows the engine rumbling of some snowmobiles and emergency vehicles. Otherwise, transport is by foot, bicycle or horse-drawn carriage.