Black Chasm Cavern National Natural Landmark

Black Chasm Cavern is a designated National Natural Landmark that features guided underground walking tours. Guests navigate over 160 steps down into subterranean chambers to view rare crystal formations and an underground deep blue lake.

Commenters share enthusiastic memories of the cavern from childhood field trips and scenic road trip detours en route to Lake Tahoe. Many also appreciate the nearby regional cultural context, noting neighboring sites like Indian Grinding Rock State Historic Park.