World Wars I and II

Destruction of both Imperial Germany and the Austro-Hungarian Empire was among the results of World War I, which engulfed Europe during 1914–18. The United States, which entered the war on the side of England, France, and the other Allied powers, contributed greatly to the Allied victory. World War I indirectly led to a revolution that overthrew Czarist Russia in 1917. In 1922 most of the territory that once made up imperial Russia united to form a Communist country known as the Union of Soviet Socialist Republics, or the Soviet Union.

The Allied statesmen drew new boundaries for several European nations and established some new nations. Along with the creation of the League of Nations, these and other arrangements were intended to assure a lasting peace. However, with the rise of Fascism in Italy and Nazism in Germany, Europe again moved toward war. Germany and Italy formed an alliance in 1936 with Japan. The three nations became known as the Axis powers. World War II began with the German invasion of Poland in 1939, and became a world-wide struggle between the Axis powers on the one hand and Great Britain, the Soviet Union, the United States, and their allies on the other. The war ended in 1945 with the defeat of the Axis powers.