World War II lasted from 1939 to 1945, involving 61 countries and resulting in 72 million deaths, initially sparked by Germany's post-WWI reparations and the rise of Adolf Hitler. Hitler, who ruled Germany from 1933 and implemented severe restrictions and persecution against Jews, sought to establish an Aryan supremacy narrative, leading to ghettos and concentration camps as part of the Holocaust. The war concluded with Germany surrendering on May 8, 1945, followed by Japan's surrender on August 15, 1945, with approximately 6 million Jews being murdered during the Holocaust.