WW1 events By facebooker_100009124154722 Jun 1, 1914 assassination of Archduke Ferdinand Jul 1, 1914 Austria Hungary declares war on Serbia starting WW1 Sep 1, 1914 Battle of Marne Period: Oct 1, 1914 to Nov 1, 1914 race to the sea May 17, 1915 sinking of RMS Lusitania Feb 17, 1917 Germany resumes unrestriceted submarine warfare Period: Nov 17, 1917 to Feb 17, 1918 Germany knocks Russia out of war Period: Mar 17, 1918 to Apr 17, 1918 Spring offensive Period: Sep 17, 1918 to Nov 17, 1918 meuse argonne offensive Nov 11, 1918 Armistice ends hostiles