causes:
nationalism
alliances (I think this is the biggest cause)
the assassination of archduke Franz Ferdinand.
I think that alliances were the biggest cause if world war 1. this is because the original dispute was only between two countries and because of the alliances the other more powerful countries had to step in. For example, the triple alliance and the triple entente were the two main alliances in ww1. Because the alliances were made up of lots of countries, they all got dragged into the dispute, causing a much bigger war than there needed to be.
so yeah idk rlly, hope this helps :)
