Nis in Serbia, famous for the Skull Tower ("chele-kula").
The Turks built the tower in 1809 from 952 Serb heads, who were killed in the Battle on ČEGAR.
In this battle, about 4000 Serbs and 10-16 thousand Turks were killed (Serb historical data).
Only 58 skulls remained today, and one of them belongs to the leader of the uprising Serbs, Stevan Sindjelic.
International Airport (Constantine the Great - Nis, Constantine the Great, 272-337, was born in Naissus; Founder of Constantinople - today Istanbul. Near the St. Sophia church there is the tomb of Emperor Constantine the Great. Catherine never conquered Constantinople - which was her goal in life: The testament of Catherine the Great from 1792):