World War I began in Europe with the assassination of Archduke Franz Ferdinand of Austria on a visit to Sarajevo, Bosnia. the united states entered the war on April 6, 1917 as result of Germany's policy of unrestricted submarine warfare which violated its neutrality. the failed final German offensive of march 21, 1918 timed to occur before significant American forces could arrive, resulted in the abdication of the Kaiser and Germany being forced to sue for peace. The battles of Chateau-Thierry, Belleau wood and the Meuse-Argonne were primary sites of the American fighting. This conflict saw more efficient methods of making war being devised. The flame thrower, the tank, the airplane and the submarine. at the end; the exhausted combatants signed the treaty of Versailles on June 28, 1919. which laid the foundation for the dictatorships that would plunge the next generation into another world war. total U.S. involvement included 4,744,000 with 53,513 hostile deaths 63,195 non-hostile deaths and 204,002 wounded.