WORLD WAR ONE By unidentifiedflailingobject Jun 28, 1914 Assassination of Archduke Ferdinand Jun 28, 1914 Austria-Hungary declares War of Serbia Period: Jun 28, 1914 to Nov 11, 1918 World War One Apr 22, 1915 Germany Fires At Allied Lines Sep 15, 1915 Great Britain Sends Out the First Tanks Feb 15, 1917 Zimmerman Telegram Apr 6, 1917 USA Declares War on Germany Jun 24, 1917 US Troops Start Going into France Dec 15, 1917 Russia signs an armistice with Germany Sep 26, 1918 Allies Begin Final Offensive Nov 11, 1918 Treaty of Versailles