Europe's tallest dam survived one of history's deadliest engineering disasters, but nearly 2,000 people below did not

On the night of 9 October 1963, one of the worst dam-related disasters in European history unfolded in northern Italy.

A massive section of Monte Toc collapsed into the Vajont Reservoir, displacing millions of cubic metres of water in seconds.

The resulting wave rose hundreds of metres above the reservoir, overtopped the dam and surged down the narrow valley below, obliterating entire communities.

Remarkably, the 261.6-metre-high Vajont Dam, then one of the tallest dams in the world, remained almost structurally intact.

It was not the dam that failed, but the mountain beside it.