Gruta de las Maravillas
The Gruta de las Maravillas (English: "Grotto of the Marvels") is a cave in the town center of Aracena, Andalusia, Spain. It was the first Spanish cave to be opened to the public in 1914. It includes a total of 2130 subterranean meters of subterranean passages. According to popular tradition, its discoverer was a shepherd, and the first historical reference of its existence dates from 1886.
Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).