@Sataraš what are you talking about? Austria-Hungary wanted to expand to on Serbia’s expense, the assassination was just an excuse for the invasion. Just look up the ultimatum Serbia was given, no sovereign country would’ve excepted that. It became a World War because of previous conflicts and disagreements since 1878 onward. Major powers grouped in various alliances before the WWI, everybody knew the war is coming, but no one expected it on such a large scale.