confluence of danube and sava river in belgrade

ancient architecture attraction background balkan beautiful belgrade beograd blue boat building buildings capital castle city confluence danube destination europe european fort fortification fortress grass green historic historical history kalemegdan landmark landscape medieval natural nature observation old outdoor panorama park river ruins sava scenery serbia serbian ship sightseeing site sky srbija stone stream stronghold summer summertime tour tourism tourist touristic tower town travel trees view viewpoint vintage wall wallpaper water