Answer: The Second World War (1939–1945) was caused by the following factors:
- Treaty of Versailles: Germany was humiliated by the treaty of 1919 — it lost territory and colonies, its army was cut down and it had to pay huge war reparations. Germans wanted revenge.
- Rise of dictatorships: Fascism under Mussolini in Italy and Nazism under Hitler in Germany rose; both glorified war and aggressive nationalism. Japan too adopted militarism.
- Failure of the League of Nations: the League could not stop Japan's attack on Manchuria (1931), Italy's invasion of Ethiopia (1935) or Germany's breaking of the Versailles terms, as it had no army and big powers like USA were not its members.
- Policy of appeasement: Britain and France allowed Hitler to annex Austria and the Sudetenland of Czechoslovakia (Munich Pact, 1938), which encouraged him.
- Rival alliances and arms race: Germany, Italy and Japan formed the Axis; the economic depression of 1929 increased unrest.
- Immediate cause: Germany invaded Poland on 1 September 1939; Britain and France declared war on Germany and the Second World War began.
