A Cave with Crystals
Crystal Cave is a Cave in Sequoia National Park. The cave is open to tours, the trail head starts 1/2 mile above the cave, you hike down, pass a waterfall and then come to the cave entrance. The cave tour is close to a mile inside the cave, then a 1/2 mile hike back up to the parking lot. The cave is about 60* inside year round. the hike down and up is short but does have some incline, its mostly paved as it sees heavy traffic. Inside the cave you see many different formations, the creek runs through the cave as well.
In order to take the cave tour you must purchase tickets in advance. Tickets are not sold at the trailhead, they are available in the Lodgepole visitors center, and there are tours every hour, on the hour. The tour lasts about an hour including the hike down. You are on your own on the way up giving you some time to explore the waterfall or the surrounding area.
Check out the Triplogs.