Erto, the main village, Casso fraction, is the westernmost municipality of Friuli Venezia Giulia and although it is not located in the morphological site of the Cellina torrent, but on the splendid Vajont Valley, it is known as part of the Valcellina, although it is separated from the Sant’Osvaldo pass. This territory is famous throughout the peninsula for the tragic episode of October 9, 1963, known as “The Disaster of the Vajont”. During the Second World War, work began on the construction of the gigantic Vajont dam. The purpose was to build a hydroelectric power plant to supply the growing electricity needs of the region. It was then the tallest dam in Europe and was completed in 1960. Subsequently, the accumulated water gnawed at the surrounding mountains causing the ground to collapse; as a result, a landslide produced a gigantic wave and more than 2000 victims.