Wind Cave National Park was established January 9, 1903. It has over 117 miles of explored passageways and is one of the longest, most complex caves in the world. Amazingly, judging from airflow at the entrance an estimated 95% of the cave still awaits discovery. Its unseen depths provide opportunities for cave explorers to experience a true frontier, a place where people have never before ventured. It is the seventh national park in the world and the first to protect a cave.