World War II, or the Second World War was a global military conflict lasting from 1939 to 1945 which involved most of the world's nations, including all of the great powers, organized 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 mobilized. In a state of "total war" the major participants placed their 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 history.

War and peace is a contradiction, is the unity of opposites. There is no absolute peace, nor permanent war. Peace and promote the development of human civilization, the war  promote the progress of human society.