The National Park Service celebrated it's centennial, Aug. 25, 2016. President Woodrow Wilson created the National Parks Service "to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same." Millions of people visit national parks every year. Here, the sun sets as Mount McKinley casts its reflection on Reflection Pond at the west end of Denali National Park Road, in Denali Park, Alaska. In August 2015, the government changed the name of North America's tallest peak from Mount McKinley to Denali.
Al Grillo/AP Photo