In probably one of the best known and most widely told stories of the Second World War, nineteen Lancaster bombers of 617 Squadron, led by Wing Commander Guy Gibson, raided the great hydroelectric dams of western Germany in May 1943. Each Lancaster was equipped with the revolutionary bouncing bomb designed by the inventor Barnes Wallis, creator of the Wellington bomber. Designed to skip over the surface of the water, the bombs rotated at 500 rpm. They had to be dropped at a speed of 240 miles an hour and were set to explode while sinking to the base of the dam's retaining wall. It took five attempts to breach the Moehne Dam. Gibson then led the three remaining Lancasters to attack the Eder Dam. The unleashed floodwaters inundated the Ruhr valley below, killing thousands and causing German industry to grind to a halt. Eight of the nineteen aircraft involved in the raid failed to return to base. Wing Commander Gibson, only twenty-four at the time of the mission, was awarded the Victoria Cross. He was killed in action sixteen months later. In later years the strategic impact of the raid was deemed to be less than was thought at the time, but the fillip it gave to civilian and Service morale in wartime Britain was incalculable. In 1954 the raid was immortalised in The Dambusters, starring Michael Redgrave and Richard Todd, who contributes a foreword to the book. A box office success, the film has become a classic, the music score being one of the best known of all time.