Colossal Cave (Arizona) Colossal Cave is a large cave system in southeastern Arizona, near the community of Vail, approximately 22 miles SE of Tucson. It contains about 3.5 miles (5.6 km) of mapped passageways, and was discovered by Soloman Lick in 1879. Temperatures inside average 70 degrees Fahrenheit (21 degrees Celsius) year-round.