This 262-Meter Dam Never Broke. Nearly 2,000 People Died Anyway

In 1963, one of the tallest dams in the world did exactly what it was designed to do. It held. And a night later, the valley below it was gone. This is the story of Vajont — a 262-metre concrete arch dam in the Italian Alps that survived one of the worst engineering disasters of the 20th century almost without a scratch. The danger was never in the concrete. It was in the mountain next to the lake: a 2-kilometre slab of rock sitting on thin layers of clay, creeping faster every time the water rose. For almost four years there were warnings — a crack on Monte Toc, a landslide into the lake, geologists' reports, a journalist put on trial for sounding the alarm. Instead of stopping, the operators tried to use the lake itself as a brake on the mountain. On 9 October 1963, at 22:39, it stopped working. In this video: why Vajont's double-curvature arch was a masterpiece of engineering how a lake can push a mountain from the inside the "brake" strategy — and why it failed the 45 seconds that sent a wave over the top of an intact dam what engineers changed afterwards, and whether it could happen again Chapters: 0:00 The dam that never broke 0:57 Why Vajont was a masterpiece 2:01 The valley starts to answer back 2:56 A mountain already on the move 4:09 Using the lake as a brake 4:56 The people who saw it coming 5:32 1963: the brake stops working 6:31 22:39, 9 October 1963 7:37 The dam held 7:57 Who answered for it 8:28 Could it happen again? 9:25 The real lesson Sources: ASDSO Dam Failures & Lessons Learned; AGU Landslide Blog; Environment & Society Portal (Arcadia); Earth Magazine; court records summarised by Italian press. The official death toll is 1,917; estimates in the literature range from about 1,900 to over 2,000. #Vajont #Engineering #DamDisaste