WWI By Jackie92557 Period: Apr 16, 1917 to Jun 21, 1918 American Invovlement Apr 17, 1917 Sinking of Luisitanias US enters the war after the Luistania, a passanger ship, was sank by a German U-Boat. Image Source: History.com http://www.history.com/topics/world-war-i/lusitania
