The Maah Daah Hey mountain-biking trail is one of the U.S.'s longest continuous singletracks – and it's usually empty. The overlooked 140-mile Badlands trail offers an expanse of crimson flattop hills and totemic spires. Book a group trip. When you first glimpse wild mustangs near the trail's south end, it won't feel any less wild.
Getting there: From the airport in Medora, the Dakota Cyclery offers shuttle rides straight to their shop, where you can grab a bike and hit the trail.