World War II

At a glance

Dates: From 1940.

What came beforeAI-assisted

World War I (1914–1918) left Germany economically devastated and humiliated by the Treaty of Versailles, which imposed harsh reparations and territorial losses. The global economic depression of the 1930s deepened resentment and instability across Europe, creating conditions for the rise of authoritarian regimes.

Japan pursued imperial expansion in Manchuria (1931) and China (1937), while Italy invaded Ethiopia (1935) and Albania (1939). These aggressions went largely unchecked by the League of Nations, emboldening further militarism.

Catalyst / how it startedAI-assisted

Adolf Hitler's Nazi Germany remilitarized the Rhineland (1936), annexed Austria (1938), and seized Czechoslovakia (1938–1939) without significant opposition. On September 1, 1939, Germany invaded Poland, prompting Britain and France to declare war two days later.

On June 17, 1940, France formally surrendered to Germany after six weeks of fighting, leaving Britain as the primary Allied power in Western Europe and marking a turning point in the war's early phase.

Who was involvedAI-assisted

The Axis powers were led by Nazi Germany (Adolf Hitler), Imperial Japan (Emperor Hirohito), and Fascist Italy (Benito Mussolini). The Allies initially included Britain and France, later joined by the Soviet Union (1941) and the United States (1941).

Over 50 nations eventually participated, including China, Poland, Yugoslavia, Greece, and numerous others. The conflict involved military forces, civilian populations, and industrial economies mobilized for total war.

TimelineAI-assisted

September 1939: Germany invades Poland; Britain and France declare war. June 1940: France surrenders; Germany occupies much of Western Europe. July–October 1940: Battle of Britain; Germany fails to invade Britain.

June 1941: Germany invades the Soviet Union. December 1941: Japan attacks Pearl Harbor; the United States enters the war. 1942–1943: Turning points at Stalingrad and Midway shift momentum to the Allies. June 1944: D-Day invasion of Normandy begins liberation of Western Europe. May 1945: Germany surrenders. August 1945: Atomic bombs dropped on Japan; Japan surrenders, ending the war.

What happened

World War II, or the Second World War, was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many engaging in total war on an unprecedented scale. World War II was the deadliest conflict in history, causing the deaths of 60 to 75 million people, a majority of whom were civilians. Millions died as a result of massacres, starvation, disease, and genocides including the Holocaust. After the Allied victory, Germany, Austria, Japan,