Monte Cucco, mainly formed by limestone rock, let the water flow through the mountain creating a cave system extended for more than 30 kilometers and with a depth of 929 meters. The caves were discovered in 1551, although it is not known who discovered them (perhaps Ludovico Carbone (theologian of Costacciaro) or by Colonel Lodivivo Santacroce (Fabriano)) the first official documentation was produced by Girolamo Gabrielli in 1720. Since 2009 the caves can be visited by the public. The interior of them is illuminated and, following an expert guide, you can safely descend into the heart of the mountain and learn its history and geological formation. Speleologists come from all over the world to discover the hidden secrets of the mountain. Two of the largest and most spectacular rooms (caves) that can be visited in this underground corridor are "The Cathedral" and "La Margherita" which rightly takes its name from the Italian-German scientist "Margherita" Mengarini Traube (1856-1912). To organize group excursions or for single people, contact the number +39 075 9171046 Email: info@grottamontecucco.umbria.it "Comune di Costacciaro".