About halfway between San Antonio and New Braunfels, this national landmark cave is one of the state’s largest underground formations. Its name comes from the 60ft limestone bridge that spans the entrance. Inside, where it’s always 70°F (21°C), are simply phenomenal formations, including the Watchtower, a 50ft pedestal that looks like a crystallized flower.
You can only see the caverns as part of a guided tour, which includes the family-friendly Discovery Tour, the Hidden Passages Illuminations Tour, or the more challenging Adventure Tours. Attached is the Natural Caverns Wildlife Park, a small zoo with rare animals.
From downtown San Antonio, take I-37 N to I-35 N, following the latter 18.5 miles to exit 175 for Hwy 3009 N. Follow Hwy 3009 for just over 8 miles to the caverns.