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What was World War II?

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Quick answer

World War II (1939–1945) was the deadliest conflict in history, fought between the Allied and Axis powers across the globe. It reshaped the world order, ended with the defeat of Nazi Germany and Japan, and ushered in the nuclear age.

Key things to understand

  1. Began in 1939 with Germany's invasion of Poland.
  2. Allies (US, UK, USSR, and others) vs Axis (Germany, Italy, Japan).
  3. Included the Holocaust and the first use of atomic bombs.
  4. Ended in 1945 and led to the United Nations and the Cold War.

People also ask

When was World War II?
From 1939 to 1945.
What caused World War II?
Aggressive expansion by the Axis powers, unresolved tensions from WWI, and the rise of fascism — triggered by Germany's invasion of Poland.
How did World War II end?
With Germany's surrender in May 1945 and Japan's surrender after the atomic bombings in August 1945.