Калемегдан
Predecessor of Belgrade was Singidunum, Celtic and, later, Roman fortified town. The original earthen and wooden fort stretched around the Studentski Trg and Knez Mihailova Street. The oldest Roman graves were discovered in this section, dated to the 1st and early 2nd century. The central axis of the city grid was in the modern Uzun Mirkova-Studentski Trg-Vasina-Republic Square direction, thus the area od modern square was the "heart" of ancient Singidunum. Part of the main axis was an additional turning at modern Rajićeva Street. There was a gate at the entrance into the military camp. The gate was located where the City Library, the last building in the Knez Mihailova Street before the Kalemegdan Park, is located today.