Boeing B-17F Memphis Belle on display in the WWII Gallery at the National Museum of the United States Air Force. B-17's flew in every combat zone during World War II, but its most significant service was over Europe. Along with the B-24 Liberator, the B-17 formed the backbone of the USAAF strategic bombing force, and it helped win the war by crippling Germany’s war industry. (U.S. Air Force photo by Ken LaRock)