The medieval fortress perched on a steep rocky crag above Sokobanja is the town's most dramatic feature and the main reason to look upward rather than downward at the valley floor. The ruins are those of a Serbian fortress from the 14th century, significantly older than the Ottoman occupation that followed, and the site commands views over the entire Moravica valley.
The climb from town takes about 30–40 minutes on a marked path. The ruins themselves are fragmentary — walls, towers, and gate structures in varying states of preservation — but the position is extraordinary. In clear weather you can see the full sweep of the valley and the hills beyond. Bring water and wear sturdy shoes; the path gets steep near the top.