Hitler wanted to unify all Germans in one state and did this by taking over places where Germans lived, such as Austria and Czechoslovakia; Hitler also wanted the land in Poland that Germany had owned before 1918, but Poland refused to give it to him. He then invaded Poland. This started World War II on 1 September 1939. In the beginning of the war, Germany was winning and even successfully invaded France. It managed to take over much of Europe. However, Germany attacked the Soviet Union in 1941 and after the Battle of Kursk, the German Eastern Front began a slow retreat until war's end. On 8 May 1945, Germany gave up after Berlin was captured, Hitler had killed himself a week earlier. Because of the war, Germany lost a lot of German land east of the Oder-Neiße line, and for 45 years, Germany was split into West Germany and East Germany. Other events happened during the war in Nazi Germany, including the Holocaust, the mass genocide of Jews and other peoples, for which some Nazis were punished in the Nuremberg Trials.