Hiking works your muscles and relaxes your mind. Go explore one of your national parks. Hike up the extinct Diamond Head volcano in Honolulu. Or make the trek up to shimmering alpine lakes in Colorado’s Rocky Mountains, Clingmans Dome in Tennessee’s Smoky Mountains, or to one of the many waterfalls in Pennsylvania’s Pocono Mountains.
Disney offers themed 5Ks to full marathons at their parks in Anaheim and Orlando. In Las Vegas, the Rock ‘n Roll Running Series is a half-marathon down the Strip after sundown. In Washington D.C., the Cherry Blossom 10-Mile Run is an annual spring event, while the fall New York City Marathon (the world's largest) is for serious runners only.