World War I, also known as the Great War, started on 28 July 1914 after the assassination of Archduke Franz Ferdinand of Austria. His murder catapulted into a war across Europe that lasted until 11 November 1918. During the four-year conflict, Germany, Austria-Hungary, Bulgaria and the Ottoman Empire (the Central Powers) fought against Great Britain, France, Russia, Italy, Romania, Canada, Japan and the United States (the Allied Powers). By the time the war was over and the Allied Powers had won, more than 16 million people—soldiers and civilians alike—were dead.

            The United States adopted a policy of neutrality. However, neutrality, however, was increasingly difficult to maintain in the face of Germany’s unchecked submarine aggression against neutral ships, including those carrying passengers. Widespread protest over the sinking by U-boat of the British ocean liner Lusitania—traveling from New York to Liverpool, England with hundreds of American passengers onboard—in May 1915 helped turn the tide of American public opinion against Germany. On 2 April 1915 President Wilson appeared before Congress and called for a declaration of war against Germany.

            At the Paris Peace Conference in 1919, Allied leaders stated their desire to build a post-war world that would safeguard itself against future conflicts of such a devastating scale. Some hopeful participants had even begun calling World War I “the War to End All Wars.” But the Treaty of Versailles, signed on 28 June 1919, would not achieve that lofty goal.

Source: History.com (30 August 2025)