European Theater of Operations, United States Army in the context of "Jack Kirby"

The Western Front was a military theatre of World War II encompassing Denmark, Norway, Luxembourg, Belgium, the Netherlands, the United Kingdom, France, and Germany. The Italian front is considered a separate but related theatre. The Western Front's 1944–1945 phase was officially deemed the European Theater by the United States, whereas Italy fell under the Mediterranean Theater along with the North African campaign. The Western Front was marked by two phases of large-scale combat operations. The first phase saw the capitulation of Luxembourg, Netherlands, Belgium, and France during May and June 1940 after their defeat in the Low Countries and the northern half of France, and continued into an air war between Germany and Britain that climaxed with the Battle of Britain. The second phase consisted of large-scale ground combat (supported by a massive strategic air war considered to be an additional front), which began in June 1944 with the Allied landings in Normandy and continued until the defeat of Germany in May 1945 with its invasion.

The Boeing B-17 Flying Fortress is an American four-engined heavy bomber aircraft developed in the 1930s for the United States Army Air Corps (USAAC). A fast and high-flying bomber used primarily in the European Theater of Operations, the B-17 dropped more bombs than any other aircraft during World War II. It is the third-most produced bomber in history, behind the American four-engined Consolidated B-24 Liberator and the German multirole, twin-engined Junkers Ju 88. The B-17 was also employed in transport, anti-submarine warfare, and search and rescue roles.

In a USAAC competition, Boeing's prototype Model 299/XB-17 outperformed two other entries but crashed, losing the initial 200-bomber contract to the Douglas B-18 Bolo. Still, the Air Corps ordered 13 more B-17s for further evaluation, which were introduced into service in 1938. The B-17 evolved through numerous design advances but from its inception, the USAAC (from 1941 the United States Army Air Forces, USAAF) promoted the aircraft as a strategic weapon. It was a relatively fast, high-flying, long-range bomber with heavy defensive armament at the expense of bomb load. It also developed a reputation for toughness based upon stories and photos of badly damaged B-17s safely returning to base.

The 6th United States Army Group (also referred to as the Southern Group of Armies) was an Allied army group that fought in the European Theater of Operations during World War II. Made up of field armies from both the United States Army and the French Army, it fought in France, Germany, Austria, and, briefly, Italy. It was established in July 1944 and commanded throughout its duration by General Jacob L. Devers.

In a lead role in Operation Undertone, its Seventh Army fought its way across the Rhine into Germany, captured Nuremberg and then Munich. Finally it crossed the Brenner Pass and made contact with the US Fifth Army at Vipiteno, Italy.