Why did World War II happen?
- Anger after World War I: the 1919 peace treaties made Germany lose land, cut its army and pay large sums. Many Germans felt humiliated.
- Great Depression (1929): banks failed, factories shut, millions lost jobs. Frightened people turned to strong leaders.
- Rise of dictators: Mussolini (Fascism, Italy), Hitler (Nazism, Germany, from 1933) and military rulers in Japan. They crushed opponents, used propaganda, built big armies and wanted to conquer land.
- Weak peacekeeping: the League of Nations could not stop attacks. Britain and France at first gave in to Hitler's demands (appeasement, e.g. Munich 1938).
The course of the war, 1939–1945
1939–1941: Axis advance
Germany invaded Poland on 1 September 1939; Britain and France declared war. Using fast tanks and aircraft (Blitzkrieg), Germany took much of Europe. France was defeated in June 1940: the north was occupied and a collaborating government ruled from Vichy, while a Free French movement and the Resistance kept fighting. Britain held out in the air battle of 1940.
1941: a truly world war
In June 1941 Germany attacked the USSR. In December 1941 Japan attacked Pearl Harbor, and the USA entered the war. Japan had been at war with China since 1937.
1942–1945: the tide turns
Key Allied victories: Midway (1942) in the Pacific, El Alamein (1942) in North Africa, Stalingrad (1942–43). The Allies landed in Italy (1943) and in Normandy, France, on D-Day (6 June 1944). Soviet forces pushed west. Germany surrendered on 8 May 1945. After atomic bombs on Hiroshima (6 August) and Nagasaki (9 August), Japan surrendered on 2 September 1945.
Total war and war of annihilation
Total war means the whole of society is used for war: factories made weapons, food was rationed, women took factory jobs, and civilians became targets of bombing.
It was also a war of annihilation. Nazi racist ideas said some peoples had no right to live. In the Holocaust (Hebrew: Shoah) about 6 million Jews, two out of every three Jews in Europe, were murdered in mass shootings and death camps such as Auschwitz-Birkenau. Roma, disabled people, Soviet prisoners and others were also killed. In the east, whole villages were destroyed. Japanese forces also committed mass killings in China and elsewhere.
We study this so that it never happens again: remember the victims, and notice early warning signs such as hate speech and taking away the rights of a group.
Results of the war
- Human cost: about 70–85 million dead, most of them civilians; millions of refugees.
- United Nations (1945) to keep peace, and the Universal Declaration of Human Rights (1948). War-crime trials at Nuremberg and Tokyo.
- Two superpowers: the USA and the USSR, whose rivalry became the Cold War. Europe was divided.
- End of empires: weakened colonial powers could not hold on; India became independent in 1947, followed by many countries in Asia and Africa.
- Nuclear age: atomic weapons changed how wars are fought and feared.
Try it: ask an elder or visit a local war memorial or museum. Note one name or story and one way the war touched your region.
Key formulas and definitions
- Axis: Germany, Italy, Japan
- Allies: Britain (and empire), France, USSR, USA, China and others
- Appeasement: giving in to an aggressor's demands to avoid war
- Blitzkrieg: "lightning war", fast attack with tanks and aircraft
- Total war: the whole society and economy used for war
- Holocaust / Shoah: Nazi murder of about 6 million Jews
- Resistance: secret fight against occupiers
- Key dates: 1 Sep 1939 start · 8 May 1945 Germany surrenders · 2 Sep 1945 end
Worked examples
1. Link the Great Depression to the start of the war in a chain of causes.
Depression (1929) → mass unemployment and fear → people vote for extreme leaders who promise jobs and pride → Nazis gain power (1933) → rearmament and land grabs → invasion of Poland (1939) → war.
2. Why is 1941 called the year the war became truly global?
Germany attacked the USSR (June) and Japan attacked Pearl Harbor (December), bringing the USA in. Fighting now covered Europe, Africa, Asia and the Pacific.
3. How many years did the war last in Europe? (1 Sep 1939 to 8 May 1945)
About 5 years and 8 months, nearly 6 years.
4. Give one cause and one result of appeasement.
Cause: Britain and France feared another huge war and were not ready. Result: Hitler became bolder and kept demanding more land, until war came anyway in 1939.
Common mistakes
- Saying the war began with Pearl Harbor: in Europe it began in 1939; Pearl Harbor (1941) brought the USA in.
- Mixing up the sides: the USSR fought with the Allies from 1941; Italy was in the Axis.
- Thinking the Holocaust was a side-effect of fighting: it was a planned, deliberate murder of a people.
- Giving one cause only: the war had several linked causes (treaties, depression, dictators, weak peacekeeping).