See

Black Chasm Cavern

About

Black Chasm Cavern is a cave in the hamlet of Volcano in Amador County, California.
From Wikipedia · Black Chasm Cave

Guide text adapted from the Wikivoyage article "Sutter Creek" by its contributors, available under CC BY-SA 4.0. Read on Wikivoyage · Contributors · CC BY-SA 4.0
Summary from the Wikipedia article "Black Chasm Cave", available under CC BY-SA 4.0. Wikipedia
Photo: Dave Bunnell / Under Earth Images, CC BY-SA 4.0 via Wikimedia Commons