On the night of May 16, 1943, RAF 617 Squadron flew modified Lancasters at sixty feet above German reservoirs to deliver Barnes Wallis's revolutionary bouncing bomb against the Ruhr Valley dams.
On the night of May 16–17, 1943, 19 Lancaster bombers and 133 airmen executed Operation Chastise, breaching Nazi Germany's Ruhr valley dams with Barnes Wallis's revolutionary bouncing bomb.