The most important events that were transcendental for and during the development of the first modern world conflict:
1) The murder of Francisco Fernando, heir of the Austro-Hungarian Empire.
2) The participation of the United States after a German submarine sank the British transatlantic Lusitania en route from New York to Liverpool, in which several American civilians lost their lives.
3) In addition, the conquest of Istanbul was in the plans of the tsars
4) Political tension between France and Germany over Morocco and between Russians and Austro-Hungarians in the Balkan area