Residents of Milan, Italy, would be able to forego their cars for a good pair of walking shoes better than most. A new study of the world's "most walkable cities" in Nature and detailed at the Economist ranks Milan as No. 1. Locals can find everything they need under a seven-minute walk, as can residents of second-place Copenhagen. As for the car-centric US, you won't find a single city in the top 50. (Or any from North America, for that matter.) The top rankings and other details: