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 civilians, were killed, making it
the deadliest conflict in
human history.
