World War II lasted from 1939 to 1945. During this tumultuous era, the world powers split into two opposing forces: the Axis powers, which mainly consisted of Germany, Japan, and Italy; and the Allies, which included the United Kingdom, China, the United States of America, and the Soviet Union. The cause of the war stemmed from a growth in fascism in Nazi Germany as Adolf Hitler took power. The war began in 1939 when Hitler invaded Poland. As Hitler grew in power, his antisemitism fueled the cruel initiative that ultimately led to the imprisonment and murder of millions of Jewish people who were forced into concentration camps. This genocide, known as the Holocaust, took the lives of almost 6 million Jews. The United States did not join the war until 1941, after the attack on Pearl Harbor. US troops then aided the Allied forces in the historic invasion of D-Day on June 6, 1944, when the Allies launched an assault on the beaches of Normandy to liberate France from Nazi occupation. After D-Day, the Allies pushed through Europe, finally winning the Battle of the Bulge in Germany; this was Germany’s last major military stand against the Allied powers in 1945.