The designation was awarded by a London-based charity that aims to make cities more like national parks: "greener, healthier and wilder" ...

During a hike in the Great Smoky Mountains National Park in 1995, Don Barger climbed Chilhowee Mountain hoping to gaze across ...

Congress amended the Clean Air Act in 1977 to make restoring and maintaining visibility a goal for 156 national parks, wilderness areas, wildlife refuges and tribal reservations across 36 states.