World War II History: Key Events and Consequences

Posted on Jun 14, 2026 in History

Key Historical Definitions

  • New World Order: Two superpowers, the USA and the USSR, emerged. The partnership between allies broke due to clashes over the future of Germany.
  • Yalta Conference: Leaders Roosevelt (USA), Churchill (UK), and Stalin (USSR) agreed to divide Germany into four occupation zones (British, French, American, and Soviet). It also confirmed the annexation of the Baltic countries and eastern Poland to the USSR.
  • Potsdam Conference: This brought together leaders Truman (USA), Attlee (UK), and Stalin (USSR). They agreed to judge Nazi war criminals (Nuremberg trials), established war reparations for Germany, and set Poland’s borders and territorial changes.
  • San Francisco Conference: The United Nations (UN) was created to ensure:
    • Maintenance of international peace and security.
    • The right of people to self-determination.
    • Defense of the rights of the individual.
    • Peaceful cooperation between people.
  • Ghetto: Quarters in which Jewish people were forced to live by the Nazis. They were overcrowded, walled, and residents died from starvation and mistreatment.
  • Molotov-Ribbentrop Pact: A non-aggression pact between Hitler and Stalin agreeing not to attack each other.
  • Munich Conference: Germany annexed the German-speaking part of Czechoslovakian territory. This was accepted by France and the UK; Hitler then invaded all of Czechoslovakia in 1939.
  • Rome and Berlin Axis: An alliance between Hitler and Mussolini.
  • Anti-Comintern Pact: An alliance between Italy, Japan, and Germany against communism.

Origins of the Second World War

  • The peace treaties of the First World War provoked Germany’s resentment.
  • The triumph of communism in Russia and the creation of the USSR.
  • The Great Depression of the 1930s.

Aggression and the Start of the War (1939)

  • Molotov-Ribbentrop Pact: Germany and the USSR agreed not to attack each other.
  • Germany wanted the Danzig Corridor in Poland.
  • Blitzkrieg (“lightning war”): Germany invaded Poland using tanks and aircraft.
  • Poland was divided between Hitler and Stalin.
  • September 3, 1939: France and the UK declared war on Germany.

War in Europe (1940–1941)

  • The USSR occupied Finland, the Baltic States, and Bessarabia.
  • Germany occupied Denmark and Norway.
  • Germany attacked Belgium through the Ardennes forest, bypassing the Maginot Line.
  • Germany invaded the Netherlands and Luxembourg.
  • France was defeated:
    • The North was occupied by Germany.
    • The South was controlled by the Vichy government under Pétain.
  • Battle of Britain: The RAF defeated German bombings; Germany failed to invade Britain.
  • Italy failed in Greece and Egypt; Germany had to provide assistance.

Operation Barbarossa (1941)

  • Hitler invaded the USSR.
  • German tanks got stuck due to bad weather and the Russian winter.

War in the Pacific

  • December 1941: Japan attacked Pearl Harbor.
  • The USA entered the war on the Allied side.
  • Japan invaded the Philippines, Malaya, the Dutch East Indies, Thailand, and Burma.
  • Naval battles occurred alongside US bombings of Japan.

Turning Points (1943–1944)

  • 1943: The USSR won the Battle of Stalingrad and pushed the Germans westward.
  • 1943: The Allies invaded Italy; Mussolini was deposed and escaped to northern Italy.
  • 1944: The Soviet army advanced toward Germany.
  • June 1944: Normandy Landings (D-Day): The Allies liberated France and advanced into Germany.

End of the War (1945)

  • The Soviets occupied Berlin.
  • Hitler committed suicide.
  • Germany surrendered.
  • The Pacific war continued; the USA suffered many casualties against Japan.
  • President Truman ordered atomic bombs dropped on Hiroshima and Nagasaki.
  • Japan surrendered, marking the end of WWII.

Consequences of the Second World War

  • More than 60 million people died.
  • Large population displacements occurred.
  • The concept of crimes against humanity arose to judge atrocities committed in concentration camps, massacres, and bombings.
  • In Central Europe, oil was scarce and industrial production had been reduced.
  • The United States, as the main producer of arms supplies for the Allies, consolidated itself as an industrial and financial power.
  • The International Monetary Fund (IMF) and the International Bank for Reconstruction and Development were created to rebuild the post-war economy and facilitate economic agreements.

The Holocaust (Shoah)

  • Jews were forced into ghettos: overcrowded, walled areas characterized by starvation and mistreatment.
  • Millions were murdered in concentration and extermination camps.