On Thursday 25 August, the U.S. National Park Service celebrates its centennial. While national parks have been around for much longer – the first national park, Yellowstone, was signed into law by President Grant in 1872 – the National Park Service which oversees them today was created by the National Park Service Organic Act in 1916 to “conserve the scenery and the natural and historic objects and wildlife therein, and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations." It administers all U.S. national parks, many American national monuments, and numerous other conservation and historical properties with various title designations. The centennial on 25 August will kick off a second century of stewardship of America's national parks and engaging communities through recreation, conservation, and historic preservation programs. There will be free admission to all 412 areas administered by the NPS from 25 to 28 August.