Malpasset Dam Disaster

The Malpasset Dam was an arch dam on the Reyran River, located approximately 7 km north of Fréjus on the French Riviera (Côte d'Azur), southern France, in the Var département. It collapsed on December 2, 1959, killing 423 people in the resulting flood. The damage amounted to an equivalent total of $68 million.

https://engineers-channel.blogspot.com/p/dams-disasters-list.html