World War 1 Time Line by Emma Mainer By egnd Jun 28, 1914 Cause of the WAR: ARCHDUKE FRANZ FERDINAND IS ASSISSINATED Jul 28, 1914 AUSTRIA-HUNGARY DECLARES WAR ON SERBIA. WORLD WAR I BEGINS May 7, 1915 GERMAN U-BOAT TORPEDOES THE LUSITANIA Feb 3, 1917 THE UNITED STATES SEVERS DIPLOMATIC RELATIONS WITH GERMANY Mar 1, 1917 UNITED STATES IS ALERTED ABOUT THE ZIMMERMAN TELEGRAM Apr 6, 1917 THE US DECLARES WAR ON GERMANY Jun 5, 1917 MILLIONS OF AMERICAN MEN REGISTER FOR SERVICE ON THE FIRST DAY OF THE DRAFT Jun 28, 1918 U.S. WAR DEPARTMENT AUTHORIZES CHEMICAL WARFARE SERVICE Jun 28, 1919 GERMANY AND ALLIES SIGN THE PEACE TREATY Jul 9, 1919 GERMANY RATIFIES TREATY OF VERSAILLES Nov 19, 1919 U.S. SENATE REFUSES TO RATIFY THE TREATY OF VERSAILLES Aug 10, 1920 TREATY OF SEVRES ENDS THE WAR ON THE EASTERN FRONT WITH THE OTTOMAN EMPIRE