September 1, 1939War & ConflictEurope

World War II Begins

Nazi Germany invaded Poland, triggering declarations of war from Britain and France and beginning the Second World War.

On September 1, 1939, Nazi Germany, led by Adolf Hitler, invaded Poland, prompting Britain and France to declare war on Germany two days later. World War II (1939-1945) became the deadliest conflict in human history, claiming an estimated 70-85 million lives, including the six million Jews murdered in the Holocaust. The war reshaped the global order, leading to the creation of the United Nations, the beginning of the Cold War, and the process of decolonization.

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