Koviljkin grad
Serbia
Koviljkin grad or Koviljka is a name for archaeological ruins close to Banja Koviljača in the Loznica district of western Serbia. The ruins are of a Roman town, which may have been named Gensis; the name has never been confirmed. It is located on the top of a hill, and the remains of the walls spread about 150 metres around it. At the time of the Roman Empire, the river Drina flowed underneath this settlement, and it is believed that there was a Roman river harbour. The site has not been completely explored by archaeologists.
Archaeological site data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).