10. Caverns of Sonora -Texas
Located halfway between Big Bend and San Antonio, the Caverns of Sonora are considered to be one of the most active caves around the U.S. with with more than 95% of its formations still growing.
Tour the caverns and experience exquisite calcite crystal formations and rare helictites including a famous helictite formation named the Butterfly of Sonora after its characteristic form.
Choose from the 1 hour 45 minute Crystal Palace Tour ($18 adults, $16 ages 4-11, free under 4) or go off the beaten path on the four-hour Discovery Challenge Tour ($125 adults only) through a maze of off-trail passageways including a 50-foot repel into the Devil’s Pit.