^
For the civil population the breaching of the dams was surely not very pleasant...
https://www.cbc.ca/calgary/features/dambusters/Operation Chastise
During the Second World War, the Allies hatched a secret plan to bomb three German dams. The Royal Air Force quickly formed Squadron 617, later known as "The Dambusters."
Nineteen Lancaster planes, led by a young pilot named Guy Gibson, launched the attack on May 16, 1943. The bombs breached two of the three hydroelectric dams, Möhne and Eder, causing deadly floods in the Ruhr Valley, an industrial heartland.