How did the assassination of the archduke Franz Ferdinand contribute to the outbreak of World War 1?
Basically the assassination caused a chain reaction, if you like, obligating nations to go to war because of treaties that were in effect before the war began. Austria-Hungary attacked Serbia in retaliation for the assassination, Russia intervened to help the Serbs, Germany joined in alongside Austria-Hungary, and France and Britain were brought in because of an alliance with Russia. Begin WW1.