World War II began as Germany, led by Hitler, sought to expand its territory by taking over countries in Europe. This caused concern in England and France, leading up tensions. Germany then invaded Poland in 1939 by making deals with Russia to divide the country between them, marking the start of World War II. During the war, Germany blamed the Jews for their losses and set up concentration camps, most notoriously Auschwitz in Poland, where many Jews were killed. The war ended in 1945 with Hitler's defeat, though massive casualties were suffered on all sides.