Soldiers then manufactured gunpowder in the cave’s chambers until the end of the war. Texas outlaw Sam Bass is thought to have used the cave as a hideout before entrepreneurs turned the chambers into a dance hall, a night club, a theater, and a restaurant. Today, the cavern is part of the state park system and guided tours are available year-round. Elsewhere among the limestone geology of the state, much of it occurring in the Hill Country region, caves and caverns delight both tourists and adventurers. Caves like Natural Bridge Caverns in New Braunfels, Cascade Caverns in Bourne, and Caverns of Sonora with its delicate butterfly-shaped helictites, offer guided, informative tours through well-lighted passages. Several of the caves open to the public also offer primitive cave touring like those at Colorado Bend State Park near Bend and Kickapoo Caverns State Park north of Brackettville. Over three thousand known caves riddle the Texas landscape and many of them are home to endangered species including our significant population of bats. Caves are also important in recharging our groundwater supplies, allowing rain and runoff to filter out impurities and refill our underground wells and aquifers, a key component in sustaining life above ground.