Late in the evening of 9 October 1963, a slope of Mount Toc collapsed into the artificial reservoir created by the Vajont dam, the highest double-arch dam in the world. The fall of this huge mass of debris, soil, and rocks displaced a quantity of water that surged in multiple directions. It primarily affected the municipality of Erto e Casso, located on the northern bank of the reservoir, causing hundreds of deaths. However, the wave also overtopped the crest of the dam and poured down the narrow, deep gorge leading into the Piave valley, reaching the municipality of Longarone. More than the force of the water itself, it was the shock wave generated by the displacement of air that caused the greatest destruction: its intensity is estimated to have been twice that of the atomic bomb dropped on Hiroshima. The official death toll was 1910, although some estimates exceed 2000.1