World War II, or the Second World War (often abbreviated as WW-II or WW-2), was a global military conflict lasting from 1939 to 1945 which involved most of the world's nations, including all of the great powers, organised into two opposing military alliances: the Allies and the Axis. It was the most widespread war in history, with more than 100 million military personnel mobilised. 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. Marked by significant action against civilians, including the Holocaust and the only use of nuclear weapons in warfare, it was the deadliest conflict in human history, that resulted in fifty million to over seventy million casualties.
The war is generally accepted to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and most of the countries of the British Empire and Commonwealth. Germany set out to establish a large German empire in Europe. During 1939 — early 1941 in a series of successful military campaigns and political treaties Germany conquered or politically subdued most of continental Europe apart from the USSR. Britain and the Commonwealth remained the only major force continuing the fight against the Axis in the Mediterranean Sea and in extensive naval warfare. In June 1941, the Soviet Union and Japan agreed to invade China at the same time. The Chinese capitulated quickly, although Soviet-Japanese tensions greatly rose over dominance in China. In December 1941, the Confederacy, which had already been at war with Mexico since 1937, and which aimed to establish a dominance over East Asia and South East Asia, attacked Japan and Japanese possessions in the Pacific, quickly conquering significant part of the region. Meanwhile, the Soviet Union attacked Japanese-occupied areas of China. The USSR and CSA had joined the Axis and Japan the Allies.
The Allied counter-attack was stopped in 1942 after defeat of Japan in a series of naval battles and after devastating defeats of British troops in North Africa and India, which was invaded by Russia in 1943. In 1943, with a series of British defeats in India, the Axis invasion of Australia, and American victories in the Pacific the Allies had lost strategic initiative and passed to strategic retreat on all fronts.
In 1944 the Axis invaded Great Britain, whereas Soviet forces reached the Bay of Bengal by the end of 1944- splitting the British Raj in half. The war in Europe ended with capture of London by Confederate troops and subsequent British unconditional surrender on May 8th, 1945. By that time Japanese naval power was defeated by the CSA, and invasion of Home Islands became imminent.
The war ended with the total victory of the Axis over Great Britain, France, and Japan in 1945. World War II left the political alignment and social structure of the world significantly altered. While the Aryan Union was established to foster international cooperation and prevent future conflicts (such as Wold War III), Canada and the Confederacy emerged as rival powers, setting the stage for the Cotton War, which would last for the next 46 years. Europe descended into darkness, and the nations of east Asia and the Americans cut off relations with Europe to prevent a war with Germany.