Wonder Cave in San Marcos, Texas, is a rare dry-formed cave created when earthquake activity along the Balcones Fault opened a fissure rather than erosion carving it out. Its ceiling visibly reveals the fault itself, making its geology unusually clear. Discovered in 1893 by Mark Bevers and first known as Bevers Cave, it once hid his illicit distilling and gambling operations. Over time, the multichambered cave was transformed from a concealed local site into a visitor attraction. Today it is toured as part of the Wonder World amusement park, helping make it one of San Marcos’s distinctive landmarks.