World War II (often abbreviated to
WWII or
WW2), also known as the
Second World War, was a
global war that lasted from 1939 to 1945, although related conflicts began earlier. It involved
the vast majority of the world's nations—including all of the
great powers—eventually forming two opposing
military alliances: the
Allies and the
Axis. It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries. In a state of "
total war", the major participants threw their entire economic, industrial, and scientific capabilities behind the
war effort, erasing the distinction between civilian and military resources. Marked by mass deaths of civilians, including
the Holocaust (in which approximately 11 million people were killed)
and the
strategic bombing of industrial and population centres (in which approximately one million were killed, and which included the
atomic bombings of Hiroshima and Nagasaki), it resulted in an estimated
50 million to 85 million fatalities. These made World War II the
deadliest conflict in
human history.
Facts, information and articles about World War II, 1939-1945