world war 1 By jmott123 Jun 28, 1914 Assassination of Archduke Ferdinand (Archduke Ferdinand)(https://www.history.com/news/did-franz-ferdinands-assassination-cause-world-war-i Aug 26, 1914 Battle of Tannenberg https://www.history.com/this-day-in-history/battle-of-tannenberg-begins Jul 31, 1917 Battle of Passchendaele
