Today it's 48th anniversary of the worst disaster ever caused in the world by a dam, the Vajont disaster. It was caused by a dam placed in a valley where an old landslide was reactivated by the lake. The enormous landslide, estimated 250 million cubic meters, fell into the lake and the wave destroyed the valley, the small city of Longarone (Belluno, Veneto, north-eastern Italy) and many other small villages, killing about 1970 people (the exact number is not known). The total energy of the landslide and the subsequent water wave was estimated to be double than Hiroshima's atomic bomb. This dam was conceived in the 1940's and built in the 1950's. It was just finished when the disaster happened. In 1963 it was the highest dam of its type, 263 meters (863 feet) over the bottom of the valley.