Strategically dominating the town, the deep Lumbardhi valley and the Dukagjini plains, the ancient fortress has been a place for defence and refuge since prehistoric times. On top of the 500-metre high Cvilen hill immediately southeast of the centre, the fortress was significantly expanded and strengthened in Byzantine and Ottoman times and was still exclusively used as a fortress until 1912. It fell in disrepair since, with no remaining structures and deteriorating walls that are currently being consolidated. A €2 million EU grant will pay for more reconstruction works in coming years. Walking up the steep path from the old town past the mainly abandoned Nën Kalaja (Pod Kalaja) district to the ruined fortress will take about 15 minutes and gets you the best views of the city centre, especially in the morning when the sun is behind you, and at sunset. A gravel path leads from the highest point of the fortress to the Lumbardhi valley, from where you can walk to the Marash district. Just to the east, the small Kalaja e Cuces (Kiz Kalasi) or 'Girl's Fortress' is also ancient, and currently home to a KFOR base.

Admission free.