The Death Star assault scene was modeled after the World War II film "The Dam Busters" (1955), in which Royal Air Force Lancaster bombers fly along heavily defended reservoirs and aim bouncing bombs at dams, to cripple the heavy industry of Germany's Ruhr region. Some of the dialogue in "The Dam Busters" is repeated in the "Star Wars" climax; Gilbert Taylor also filmed the special effects sequences in "The Dam Busters". In addition, the sequence was partially inspired by the climax of the film "633 Squadron" (1964), directed by Walter Grauman, in which RAF de Havilland Mosquitos attack a German heavy water plant by flying down a narrow fjord to drop special bombs at a precise point, while avoiding anti-aircraft guns and German fighters. Clips from both films were included in Lucas's temporary dogfight footage version of the sequence. There are also similarities in the Death Star trench sequence to the bridge attack scene in "The Bridges at Toko-Ri".