The Frasassi Caves are a karst cave system in the municipality of Genga, Italy, in the province of Ancona, Marche. They are among the most famous show caves in Italy.
Wikipedia https://en.wikipedia.org/wiki/Frasassi_Caves
Address Frazione San Vittore, 60040, Italy
Coordinates 43°24'1.347" N 12°57'39.909" E