Hamilton Preserve – a natural pool, which appeared when the dome of an underground river collapsed thousands of years of erosion by the action. The pool is surrounded by huge slabs of limestone, which lie at the water’s edge. From the ceiling, above, grow huge stalactites. Hamilton Creek River flows directly from these limestone slabs, creating a 15-meter waterfall that drops straight into a steep canyon. Waterfall never dries out completely, but in times of drought it becomes slower and shallower. However, the water level in the basin is the same even in periods of drought. The pool is located about 23 miles (37 km) west of Austin, Texas off Highway 71.