Endless views stretching to the sea await adventurers in Maine’s Acadia National Park, which has more than 150 miles of trails to explore. To guide hikers and protect fragile plants and soils, trail builder Waldron Bates created small, artfully arranged rock piles, or cairns. Bates cairns have shown hikers the way for more than a century – by walking at Acadia, you’re following in the footsteps of history. Photo courtesy of James Kaiser.