Operation Argument (‘Big Week’): The beginning of the end of the German Luftwaffe
B-17 formation under attack during a bombing raid on an industrial target in Germany, probably sometime in 1943. By fall 1943, German antiaircraft defenses—fighters, ground-based anti-aircraft artillery batteries and specially designed flak towers around key industrial centers—had become quite formidable. The black smoke dots came from exploding AAA shells, fitted with proximity fuses. (U.S. Air Force photo)