World War II

World War II, or the Second World War (often abbreviated WWII or WW2), was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis. The war involved the mobilization of over 100 million military personnel, making it the most

widespread war in history. In a state of "total war", the major participants placed their entire economic, industrial, and scientific capabilities at the service of the war effort, erasing the distinction between civilian and military resources. Over seventy million people, the majority of whom were civilians, were killed, making it the deadliest conflict in human history. The start of the war is generally held to be September 1, 1939, with the German invasion of Poland and subsequent declarations of war on Germany by most of the countries in the British Empire and Commonwealth, and by France. Subsequently, the Soviet Union invaded Poland from the east side. Many countries were already at war before this date, such as Ethiopia and Italy in the Second Italo-Abyssinian War and Nationalist China and Japan in the Second Sino-Japanese War, and