The Black Hands terrorist organization, the ones that killed Archduke Ferdinand, hoped that by doing so they would start a civil war that would result in a victory for Serbia, specifically creating a "Greater Serbia" from the dissolution of the Austro-Hungarian Empire where they had dominance over their regional neighbors.

Obviously, that didn't happen.

Instead WW1 happened.

Which ended in the dissolution of the Austro-Hungarian Empire and the creation of Yugoslavia, a constitutional monarchy with a Serbian royal family, capital in Serbia.

(And then they made everyone hate them because they were assholes both as a monarchy and a communist state)

Second, Bonus Fun History Fact:

Terroristic tactics have left Afghanistan as the only nation to have defeated occupations by the British Empire, the Soviet Union, and America, the three most powerful states since the collapse of the Mongol Empire.