Caves, Lava Tubes and Mines

Entrance to Blue Grotto, Photo by David HaysValentine Cave, Photo by Jean Krejca Zara, Environmental LLCHeppe Ice Cave, Ice Pool, Photo by David HaysLava Beds National MonumentLava Beds National MonumentLava Beds National MonumentLava Beds National MonumentLava Beds National MonumentValentine CaveSkull CaveGillems BluffValentine CaveOak Hollow Creek cave entrance, Highway 96, CaliforniaMining Shacks