Serbia: Belgrade – Belgrade Fortress

Belgrade Fortress aka Kalemegdan Fortress stands high above the city with sweeping views of the confluence of Sava and Danube rivers  and the old town (Stari Grad). The fortress was founded in 279BC during the Roman Empire and has been expanded and fortified ever since. The fortress is massive and takes a good part of the day to explore all the viewpoints, towers, walls, and museums.