Most avid hikers end up with a favorite trail or two that they visit over and over, watching the seasons change over familiar terrain. But the U.S. is rich in scenic hikes — so for those who want to explore new territory or just get a great workout, here's a collection of the best hikes in every state. We chose trails that are popular both with novices and experts and that are challenging enough to get your heart pumping, but with scenery magnificent enough that you won't mind the workout. Just make sure you research your destination before you go. For instance, Hawaii's Diamond Head has started requiring reservations for out-of-staters.