View of one of the large halls of the Rheinmetall-borsig Armament factories at Duesseldorf, Germany, on August 13, 1939, where gun barrels are the main output. Before the start of the war, German factories were cranking out pieces of military machinery measured in the hundreds per year. Soon it climbed into the tens of thousands. In 1944 alone, over 25,000 fighter planes were built. (AP Photo) #