17 May 1943
Just after midnight, on the night of 16/17 May 1943, Lancaster crews of 617 Squadron undertook what was to become the most remarkable and probably best-remembered air raid of the Second World War. Flying all the way from their base in England in darkness at tree-top height, with just the light of the moon to guide them, the specially selected crews made a surprise attack on the mighty hydro-electric dams in the Ruhr.

Flying specially modified aircraft, each Lancaster was equipped with the unique cylindrical hydro-statically detonated bomb as conceived by Barnes Wallis. This huge device when released from the aircraft flying at exactly 230mph and at the precise height of 60 ft spun onto the surface of the water. To achieve the critical height above the water at moment of release, two beams of light, from front and aft, were projected from the aircraft on to the surface of the water, creating a neat figure-of-eight on the surface below. As each bomb bounced across the water towards its target, it struck the dam wall, sank to the pre-set depth, and exploded. The results were devastating.

Led by the mercurial Squadron Leader Guy Gibson, ignoring furious defensive gunfire while flying perilously close to the water, each crew made their precision run at the target, released their deadly bomb, and those lucky enough to survive the barrage of tracer shells and anti-aircraft fire, escaped into the darkness. Not all of them did.

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