Žrnov

Žrnov, also known as Žrnovan, was a historic fortress situated on the highest peak of Avala Mountain at an elevation of 511 meters in Belgrade, Serbia. While the site originally served as a Celtic outpost due to the region's rich deposits of lead and cinnabarite, the Roman Empire later constructed a fortified installation there to protect valuable mining operations and control access roads to Singidunum, the ancient predecessor of Belgrade. During the medieval period, specifically under the rule of Serbian Despot Stefan Lazarević in the early fifteenth century, the structure was significantly expanded into a proper fortress known as Žrnov Grad. The name likely derives from the large grinding stones used locally to crush ore, reflecting the site's long-standing connection to metallurgy and mineral extraction.

The fortress saw further modifications after the Ottoman conquest in 1442, when the eastern and southern ramparts were strengthened to enhance its defensive capabilities. Throughout the Middle Ages, the mountain's cinnabarite remained economically significant, being utilized for fresco paintings and exported to Greece. Despite its strategic importance across various eras, including Roman, Serbian, and Ottoman rule, detailed historical records regarding its specific architectural evolution remain scarce. Nineteenth-century traveler Felix Philipp Kanitz documented the ruins through drawings, noting its construction atop earlier Roman foundations, though exact timelines of imperial involvement were not fully specified in his accounts.

In a tragic turn for heritage preservation, the entire fortress was completely demolished in 1934 to clear space for the construction of the Monument to the Unknown Hero. During the demolition process, archaeologists discovered remnants of the Roman layer, including a water cistern and a bread-baking oven, offering brief glimpses into daily life at the ancient outpost. Today, no physical traces of Žrnov remain standing, as the site is entirely occupied by the modern memorial. Its legacy persists primarily through historical texts and illustrations that recall its role as a guardian of Avala's矿产资源 and a strategic military point for centuries before its destruction.