Hi, war is a world that carry many negative feeling with itself like death, paucity, and many other problems for the country. And it causes not just fo the failure country but also for the winner country in the war. In fact war is harmful for both winner and failure country. I hope very soon every countries understand it and ignore any war and even conflict between each other. For the first world war there was some causes like Militarism, alliances, imperialism, and nationalism which they played an important role in world war 1. Let's watch the video of causes of world war 1.