Sierra Nevada Recreation Corporation runs five "underground adventure" locations: Black Chasm, National Natural Landmark; Boyden Cavern, California Cavern, State Historic Landmark; Moaning Cavern, and Sutter Gold Mine Tours. Guided tours are offered at each location and picnic tables provided for to enjoy their meals or snacks in the scenic beauty of the properties. Two of the locations offer challenging adventure activities: Moaning Cavern has the Rappel and Adventure Trip and California Cavern has the Mammoth Cave and Middle Earth Expeditions. In addition, we have added above ground Gemstone Mining at all of our properties in the Gold Country and free sign-posted nature trails at California Cavern and Moaning Cavern. Visitors to Black Chasm can ask for a map to take the free nature hike. Sutter Gold Mine also offers free movies in the Gold Theatre on the history of gold mining and above ground gold panning.