Colossal Cave (Arizona)

Colossal Cave is a large cave system in southeastern Arizona, United States, near the community of Vail, about 22 miles (35 km) southeast of Tucson. It contains about 3.5 miles (5.6 km) of mapped passageways. Temperatures inside average 70 °F (21 °C) year-round.^[1] Previous names include 'Mountain Springs Cave' and 'Five–Mile Cave'.^[2]

The cave is an ancient karst cave, classified as "dry" by guides (though this is not a speleologic term). The meaning of this is that its formations are completely dry, or "dead", and do not grow. This is because the cave was formed by water depositing limestone, but this source has disappeared. It instead feeds the "active" nearby Arkenstone Cave that continues to grow formations. Colossal Cave was used from 900 to 1450 AD by the Hohokam, Sobaipuri, and Apache Indians.