Treaty of Versailles: A peace treaty signed after World War I that placed blame on Germany, imposed reparations on them, and caused political instability across Europe.
Great Depression: A severe worldwide economic downturn that started with stock market crashes in 1929. It lasted throughout much of the interwar years.
League of Nations: An international organization founded after World War I to promote peace and prevent future conflicts. It was replaced by the United Nations after World War II.