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. The dam was damaged but remained virtually intact. The hill behind the dam is the landslide.