Wind Cave National Park, South Dakota:
American Indian stories dating back centuries speak of a "hole that breathes cool air" in the Black Hills. Cowboys came across a breathing hole in 1881 and the exploration of Wind Cave began. In 1903 Wind Cave became the first cave anywhere in the world to be designated a national park. Cave explorers are still finding new rooms and passages in Wind Cave, the fourth longest cave in the world. The cave is well known for its outstanding display of boxwork, an unusual cave formation composed of thin calcite fins resembling honeycombs.