Operation Chastise was an attack on German dams carried out on 16–17 May 1943 by Royal Air Force No. 617 Squadron, subsequently publicised as the "Dam Busters", using a specially developed "bouncing bomb" invented and developed by Sir Barnes Wallis. The Möhne and Edersee Dams were breached, causing catastrophic flooding of the Ruhr valley and of villages in the Eder valley; the Sorpe dam sustained only minor damage. Two hydroelectric power stations were destroyed and several more were damaged.