These raids were used to cut the power to the industrial heart of the Third Reich. The daring flights were made by 617 Squadron flying Lancaster's that dropped a specially designed bomb that skipped on the water and settled to the base of the dam after contact before going off. Out of 19 aircraft that were dispatched on the mission, 8 were lost and a total of 53 of the 153 airmen were killed. The mission resulted in both primary dam trgets being breached.
Here is a video taken from the flight