The Second World War, often called World War II and abbreviated to WWII, was a world spanning military conflict between the forces of the Allied Powers, led by the US, Great Britain and France along with China and the Axis Powers, led by Nazi Germany, Fascist Italy and Imperial Japan. It was single-handedly the worst war to have ever occurred in Human history, with at least 250 million men and women called to fight and over 125 million casualties. This included the Jews, Poles and Slavs in Nazi Germany and the Chinese, Americans and Filipinos in Imperial Japan.