when and where did the first world war start
The trigger for the war was the assassination of Archduke Franz Ferdinand of Austria, heir to the throne of Austria-Hungary, by Yugoslav nationalist Gavrilo Princip in Sarajevo on 28 June 1914. This set off a diplomatic crisis when Austria-Hungary delivered an ultimatum to the Kingdom of Serbia and, as a result, entangled-international-alliances, formed over the previous decades, were invoked. Within weeks the major powers were at war, and the conflict soon spread around the world.