Take a walking tour of Boyden Cavern, located in Sequoia and Kings Canyon National Parks. Tours last approximately 45 minutes and depart on the hour. Popular sites include Bat Grotto, where bats hang out (literally) and sleep on summer days. Visitors also have the option to go on rappelling and canyoneering tours, and are given semi-waterproof backpacks, helmets, hiking shoes and other climbing gear.
Note: It’s an uphill hike to Boyden Cavern, privately owned and operated. Also, babies cannot be in back carriers during the tours — only front packs/slips.