Crystal Cave
Show Cave · Three Rivers, California
A marble cavern inside Sequoia National Park, discovered by two fishermen in 1918 and opened to visitors in 1940, with polished formations and an underground stream running through it. Getting in requires a ticket bought online days ahead and then a steep half-mile walk down from the car park — neither of which is obvious until you are already in the park.
Crystal Cave Road, Sequoia National Park, Three Rivers, California, 93262, United States
Seasonal, roughly late spring to early autumn. Tickets online in advance only. Verify current status before travelling.