Caverns of Sonora

The Caverns of Sonora, a National Natural Landmark, is a unique cave located 8 miles (13 km) west of the small city of Sonora, the seat of Sutton County, Texas. It is a world-class cave because of its stunning array of calcite crystal formations, especially helictites. These helictites are found in extreme abundance, often with a rare purity and complexity. One formation is so densely packed with them, it has been dubbed the "snake pit". The founder of the National Speleological Society, Bill Stephenson, said of the cave after his first visit: "This is the most indescribably beautiful cave in the world, its beauty cannot be exaggerated, not even by a Texan."

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).