Karen Berger has hiked thousands of miles of trails in the national parks of the United States. She is the author of twenty books, including America s Great Hiking Trails and America s National Historic Trails. Jonathan Irish has photographed on all seven continents and in more than eighty countries. For the 2016 National Park Service Centennial, Irish went on assignment to photograph all of America s national parks. Sally Jewell served as U.S. secretary of the interior from 2013 to 2017, overseeing the nation s national parks, wildlife refuges, and public lands under President Barack Obama. With more than 1.6 million members and supporters, the National Parks Conservation Association is the voice of America s national parks. With more than 1.6 million members and supporters, National Park Conservation Association is the voice of America s national parks, working to protect and preserve the nation s most iconic and inspirational places for present and future generations.