As soon as I descend the stairway leading into Longhorn Cavern, the temperature drops. A great rush of air envelops me while water drops fall from the natural rock bridge overhead. Looking up, I see hanging vines descending from one of the sinkholes, and just beyond them, a clear sky.
The entrances at Longhorn Cavern State Park, an hour and a half northwest of Austin, originated as sinkholes, or dolines. The holes began forming 500 million years ago when rainwater seeped inside of pores and fractures in the area’s limestone and pooled in depressions, causing the roof to collapse.
“Surface water began to enter the sinkhole and push its way through the hillside,” says park manager Evan Archilla, who is leading me on a tour of the cavern. The water
