"There were a lot of political problems in Europe at the time and the tension was high. The trigger for the war was the assassination of Archduke Franz Ferdinand of Austria on 28 June 1914. He was killed by a Bosnian Serb. Austria seeked revenge against Serbia which led to several alliances. within weeks Europe was at war."@en . "There were a lot of political problems in Europe at the time and the tension was high. The trigger for the war was the assassination of Archduke Franz Ferdinand of Austria on 28 June 1914. He was killed by a Bosnian Serb. Austria seeked revenge against Serbia which led to several alliances. within weeks Europe was at war."@en . . . "Why did world war one start"@en .