Almost blending in with the surrounding rocks, the Kaleto Fortress was originally built by the Romans and later expanded by the Byzantines, Bulgarians and Turks. Most of what you see today was completed in the 1830s. You can wander round three courtyards and explore the defensive bunkers; accessing the highest rocks involves a precarious climb up steep ladders.
The fortress lies about 1km west of the centre. The location is signposted. To find it, follow ul Tsolo Todorov uphill to the end of the street.