World War I lasted from August 4, 1914 to November 11, 1918. It involved many of the countries of Europe as well the United States and other nations throughout the world. More than 10 million people were killed and more than 20 million wounded. The breakdown of old alliances among European powers and an arms race led by Germany helped set the stage for the conflict, which was sparked by the assassination of Archduke Ferdinand of Austria in 1914. Hostilities began on August 4, 1914 when Germany invaded Belgium. The Allied Powers (led by Britain, France, and the United States) defeated the Central Powers (led by Germany, Austria-Hungary, and the Ottoman Empire). Allied Power Russia left the war after the Russian Revolution of 1917. The war ended the German Empire, the Austro-Hungarian Empire, Ottoman Empire, and the Russian Empire. The Treaty of Versailles (1919) severely punished Germany as the alleged instigator of the war.