Germany's first major defeat refers to the significant loss suffered by the German military during the Battle of Stalingrad in World War II, which occurred between 1942 and 1943. This defeat marked a crucial turning point in the war, leading to a shift in momentum against the Axis powers and highlighting the resilience of the Soviet Union. The failure at Stalingrad not only drained German resources but also emboldened Allied forces, ultimately contributing to the downfall of Nazi Germany.