Your answer would be the assassination of Archduke Ferdinand. This is one of the main reasons that started conflict and ended up having a world war. Archduke Ferdinand was a member of the imperial Habsburg dynasty, and a lot of people had respect for him. A terrorist from Serbia named Gavrillo Princip assassinated him, and that made a huge out burst. Because of the assassination of Archduke Ferdinand, the two countries had a lot of drama between each other, making them look for other countries to ally with to make their military's stronger, which led to them using that power against each other at war. If Archduke Ferdinand wasn't assassinated, the outcome of this world would be different. There were many events that caused Europe to get mad and wanting to get into war, but this particular event is the main reason that threw Europe off and made them go to war.
is it multiple choice