Our adventure out West last year took us to a number of national parks—Yellowstone, Devil’s Tower, the Badlands, Mt. Rushmore, and Indiana Dunes National Lakeshore. Although our visits varied—hiking here, a ranger program there, and kiddos working to complete Junior Ranger badges—there was one thing we did at every national park: We stamped our NPS passports. If you don’t already have your own passport to the national parks,