Adolf Hitler was an Austrian-born German politician who served as the dictator of Nazi Germany from 1933 until his suicide in 1945. He rose to power as the leader of the Nazi Party, becoming the chancellor in 1933 and then assuming the title of Führer und Reichskanzler in 1934. His invasion of Poland on 1 September 1939 marked the beginning of the Second World War. He was heavily involved in military operations throughout the war and played a central role in the Holocaust, the genocide of about six million Jews and millions of other victims.

Born in Braunau am Inn in Austria-Hungary, Hitler was raised near Linz and later moved to Vienna before relocating to Germany in 1913. He served in the German Army during World War I and was decorated with the Iron Cross. In 1919, he joined the German Workers' Party (DAP), the precursor to the Nazi Party, and became its leader in 1921. After a failed coup attempt in Munich in 1923, he was imprisoned and dictated the first volume of his autobiography and political manifesto, Mein Kampf (My Struggle).

Upon his release, Hitler gained popular support by denouncing the Treaty of Versailles and promoting pan-Germanism, antisemitism, and anti-communism. He became chancellor in 1933, and with the passing of the Enabling Act, began transforming the Weimar Republic into Nazi Germany, a one-party dictatorship. Upon the death of President Paul von Hindenburg in 1934, Hitler consolidated absolute power, becoming both head of state and government.

Under Hitler's regime, numerous racist policies were implemented, targeting Jews and other minorities. His aggressive foreign policy aimed to secure Lebensraum (living space) for German people, leading to the outbreak of World War II. Despite initial territorial gains, the tide of war turned against Germany, leading to its defeat in 1945. On 29 April 1945, Hitler married Eva Braun in the Führerbunker in Berlin; the next day, they both committed suicide to avoid capture by the Soviet Red Army. Their bodies were burned as per Hitler's instructions.

The Nazi regime, under Hitler's leadership, was responsible for the genocide of six million Jews and millions of others deemed 'Untermenschen' (subhumans) or socially undesirable. Hitler's policies and military actions resulted in the deaths of countless civilians and the devastation of Europe, marking World War II as the deadliest conflict in history.