In 1941, World War II was ongoing, with major events shaping the conflict. The United States entered the war after the surprise attack on Pearl Harbor by Japan on December 7, which led to a declaration of war against Japan the following day. This marked a significant turning point, as the U.S. began to mobilize its military and industrial resources. In Europe, the Nazi regime, led by Adolf Hitler, continued its aggressive expansion, invading the Soviet Union in June 1941. This operation, known as Operation Barbarossa, opened a brutal front on the Eastern European battlefield, significantly impacting the course of the war.