This karst cave system is is believed to be more than 34 million years old. Though typically known as the Pertosa Caves, cave system is also known as Grotte dell’Angelo (Angel Caves), in honor of Saint Michael the Archangel, or Grotte di Pertosa-Auletta, for the two municipalities where most of the caves are located.

Almost two miles (three kilometers) long and still not completely explored, the Pertosa Caves are connected with the phreatic zone of the Alburni Mountain range in southern Italy’s Cilento and Vallo di Diano National Park. The water coming out of the phreatic zone forms an underground river that passes through the cave system and later joins the Tanagro River.