World War I

World War I was triggered by the assassination of Archduke Francis Ferdinand, the heir to the Austro-Hungarian Empire, on June 28, 1914, in Sarajevo, Bosnia. The war started a month later, when Austria-Hungary declared war on Serbia. Other European countries soon made their own declarations of war. Great Britain entered on August 4, 1914, after Germany began its invasion of France. The war between the Allied and Associated powers (France, Russia, Great Britain, and the United States as well as numerous other nations) and the Central powers (Germany, Austria-Hungary, and Turkey) raged until 1918. The number of total casualties was extraordinary, estimated at ten million. France lost more soldiers than did Great Britain or Germany. One tenth of the French population was killed or went missing during the war. The French economy suffered as industrial and agricultural production fell to less than half of prewar levels.

In the aftermath of...