Moaning Cavern, near Vallecito in California’s Gold Country, is a solutional cave formed in marble of the Calaveras Formation and is famed for the largest single cave chamber open to the public in California. Entering written record on December 7, 1851, after its modern discovery by gold miners, it took its name from eerie sounds once heard at the opening. Enlarged for public access in the early 20th century, it became a tourist destination with stairs descending into a chamber more than 121 feet high. The cavern is also archaeologically important for human remains and other material, including finds associated with deposits estimated at about 12,000 years old.