During World War II, Ukraine was a major battleground, suffering immense devastation and loss of life. Initially part of the Soviet Union, it was invaded by Nazi Germany in 1941 during Operation Barbarossa. The German occupation led to mass executions, forced labor, and the Holocaust, with cities like Kyiv and Kharkiv witnessing atrocities such as the Babi Yar massacre. Ukrainian resistance movements, including Soviet partisans and the Ukrainian Insurgent Army (UPA), fought both Nazis and Soviets. By 1944, the Red Army had retaken Ukraine, but the war left millions dead and the country in ruins.