These caverns, south of Tucson, were apparently unknown to man until 1974, when two amateur cavers found a narrow crack in the bottom of a sinkhole, and followed the source of warm, moist air toward what ended up being more than 2½ miles of pristine cave passages. They kept this secret for 14 years, during which time they decided the best way to preserve the caverns was to develop it as a cave tour.With funding from the Kartcnher Family, the caves were finally opened in 1988.
Within these mighty limestone caverns, filled with spectacular 500,000 year old speleothems, the most impressive chambers are the Big Room, Echo Passage and the Cul-de-Sac Passage.