Ключевые слова: 87, adventure, aerial, black hills national forest, boulder, cars, climb, custer state park, discover, environment, erosion, explore, feature, fir, formation, geological, helicopter, landscape, mineral, mountain, natural, nature, needles highway, outdoor, outside, park, pine, place, preservation, public, quartz, recreation, road, rock, route, season, sky, south dakota, space, spires, spring, sunshine, tourism, trees, unique, united states, view,