Their tourism industry is singlehandedly kept afloat by vacationing metal bands.
The Skull Tower, aka Cele Kula, dates back to 1809, when Serbia was still under Ottoman control. The First Serbian Uprising wasn't going too well, and the rebels were waging a losing battle against 36,000 surly, mustachioed Turks. But rebel leader Stevan Sindelic wasn't about to let his men be immortalized on the bitch side of history. During one desperate last stand at Cegar Hill, he fired a round into a keg of gunpowder inside a fully stocked armory, triggering a massive explosion which killed him and his men ... along with all the Turkish soldiers storming their trenches.
Hellbent on posthumous revenge, the Turks collected the slain rebels' bodies and decapitated them. 952 rebel heads were skinned, and the skins filled with straw and sent to Constantinople as trophies. The skulls were used to decorate a 15-foot-high stone tower which the Turks built right at the entrance of the town.
Scenic Nis: Come for the culture, stay because you've been decapitated.
The Skull Tower was intended as a reminder to never mess with the Ottomans, but this showed a fundamental lack of understanding of human nature: Now armed with a kickass "blaze of glory" story and a metal as fuck skull tower, the Serbs doubled down. In 1815, they rebelled again, ultimately winning independence in 1830.