How it happened again: the causes
World War II grew directly from World War I's wreckage. The Treaty of Versailles humiliated Germany; the Great Depression threw millions out of work worldwide; and in that desperation, fascist leaders promised national greatness — Hitler in Germany, Mussolini in Italy, militarists in Japan. Fascism promised order and glory at the cost of freedom, and it blamed scapegoats, especially Jewish people.
The democracies tried appeasement — giving in to demands to avoid another war. Britain and France let Hitler rearm and annex Austria, then at Munich in 1938 handed him Czechoslovakia's borderlands ('peace for our time' lasted under a year). When Germany and the USSR signed a surprise nonaggression pact, Hitler invaded Poland on September 1, 1939 — and Britain and France declared war two days later.
- Versailles resentment + Great Depression = fascism's opening
- Axis: Germany, Italy, Japan · Allies: Britain, USSR, US, China, France and more
- Appeasement: giving in to Hitler's demands to avoid war
- Munich 1938: Czechoslovakia sacrificed for 'peace'
- Germany invades Poland, September 1, 1939: the war begins
Europe's story in five numbers: 1939 Poland falls (war begins) · 1941 Pearl Harbor (the US enters) · 1942–43 Stalingrad (the tide turns in the east) · 1944 D-Day (the western front opens) · 1945 Germany and Japan surrender. Chant it: Poland, Pearl, Stalingrad, D-Day, done.
Turning points: Pearl Harbor to V-J Day
December 7, 1941: Japan attacked Pearl Harbor, killing about 2,400 Americans and ending US neutrality overnight. In 1942 the tide turned twice. In the Pacific, the Battle of Midway (June 1942) destroyed Japan's carrier advantage and put it on defense. On the Eastern Front, the months-long Battle of Stalingrad (1942–43) ended with an entire German army surrendering — the war's bloodiest battle and the death of Germany's advance. Behind the lines, the Holocaust — Nazi Germany's systematic murder of six million Jewish people, plus millions of others — continued, the war's deepest crime.
Then D-Day — June 6, 1944 — landed Allied forces on the Normandy beaches, opening the western front. The liberation of Western Europe rolled east while the Soviets pushed west from Stalingrad. Germany surrendered in May 1945 (V-E Day). The Pacific war ended in August 1945 after the US dropped atomic bombs on Hiroshima and Nagasaki; Japan formally surrendered September 2 (V-J Day).
- Pearl Harbor: December 7, 1941 — the US enters the war
- Midway, June 1942: the Pacific turning point
- Stalingrad, 1942–43: the Eastern Front turning point
- D-Day, June 6, 1944: the Allied landings in Normandy
- V-E Day May 1945 · atomic bombs August 1945 · V-J Day September 1945
Aftermath: a remade world
The war killed roughly 70–85 million people, soldiers and civilians alike, and ended with the first — and so far only — wartime use of nuclear weapons. The Nuremberg trials held Nazi leaders accountable for newly defined 'crimes against humanity,' and the full horror of the Holocaust pushed human rights into international law, starting with the Universal Declaration of Human Rights.
Two superpowers stood above the rubble — the United States and the Soviet Union — and their rivalry became the Cold War. The United Nations (founded 1945) replaced the failed League of Nations, this time with the US in it. US Marshall Plan money rebuilt Western Europe while the USSR sealed off its half behind the Iron Curtain, and weakened European powers began losing their colonies. WWI remade maps; WWII remade the whole world order.
- United Nations founded, 1945 — with the US in it this time
- Nuremberg trials: leaders held accountable for war crimes
- Marshall Plan: US aid rebuilt Western Europe
- US and USSR emerge as rival superpowers → the Cold War
- Decolonization: empires crumble over the next 30 years
Key concepts to memorize
🎯 Study tips for this topic
- Chain the causes out loud: Versailles → depression → Hitler → appeasement → Poland. Tests love the chain.
- Memorize the five-number spine: 1939, 1941, 1942–43, 1944, 1945.
- Separate the two war stories — Europe vs. Pacific — then connect them at Pearl Harbor and V-J Day.
- Flashcard the battles with their 'why it mattered' line, not just the date.
- Practice one-sentence answers for 'how did WWII start?' and 'how did it end?' — those two questions carry most exams.
