1. California Cavern, State Historic Landmark
Coordinate: 38.20177, -120.50879
(www.californiacavern.com)
2. Crystal Cave
Rio Frio, Texas
Coordinate: 29.5837562, -99.740356
3. Evexia Salt Cave
1583 S. Calumet Road, Chesterton, IN 46304
Coordinate: 41.596806248, -87.0466300238
Phone: +12197286791 (www.evexiasaltcave.net)
4. Goblin Underpass
Patten Road, Lookout Mountain, GA 30750
Coordinate: 34.9735, -85.34912