Old Spanish Treasure Cave
The Old Spanish Treasure Cave is located on Hwy 59 between Sulphur Springs and Gravette, Arkansas in the northwest corner of the state. It has been a popular tourist attraction since at least 1908. It is still open to the public, with guided tours and other activities such as panning for treasure and finding fossils.
Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).