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Germany invades Belgium and Britain declares war on Germany.
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July 28: Outbreak of World War I following the assassination of Archduke Franz Ferdinand of Austria by a Serbian nationalist.
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Japan declares war on Germany.
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The United States enters World War I on the side of the Allies.
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The Bolshevik Revolution occurs in Russia, led by Vladimir Lenin and the Communist Party.
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Armistice signed between the Allies and Germany, ending World War I.
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Benito Mussolini becomes Prime Minister of Italy and establishes the fascist regime.
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The Wall Street Crash marks the beginning of the Great Depression in the United States.
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Adolf Hitler becomes Chancellor of Germany and begins the Nazi regime.
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Franklin D. Roosevelt is inaugurated as President of the United States and implements the New Deal to combat the Great Depression.
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Outbreak of the Spanish Civil War between the Republicans (supported by the Soviet Union) and Nationalists (supported by Nazi Germany and Fascist Italy).
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Japan signs the Anti-Comintern Pact with Nazi Germany, aimed at countering the spread of communism.
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Anschluss occurs as Germany annexes Austria.
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Munich Agreement is signed, allowing Germany to annex the Sudetenland region of Czechoslovakia.
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Nazi Germany and the Soviet Union sign the Molotov-Ribbentrop Pact, agreeing to divide Eastern Europe between them.
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Germany invades Poland, marking the beginning of World War II.
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Britain and France declare war on Germany.
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Germany launches Operation Barbarossa, invading the Soviet Union. December 7: Japan launches a surprise attack on Pearl Harbor, bringing the United States into World War II.
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Tehran Conference is held between the leaders of the Allied powers (Britain, the United States, and the Soviet Union) to plan the strategy for defeating Nazi Germany.
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Soviet forces liberate Auschwitz concentration camp.
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Adolf Hitler commits suicide in his bunker in Berlin.
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The United States drops atomic bombs on Hiroshima and Nagasaki, leading to Japan's surrender and the end of World War II.