The ancient city of Klos (Nikaia) it is situated in the proximity of Byllis (ca.1 km), with a wall about 1850m long, covering an area of ca.18 ha. The wall represents one of the earliest fortifications of the second half of the 5th century B.C. in Albania, being 3-3.5m wide, with polygonal and trapezoidal blocks. There is a single entrance to the city and three defensive towers.
Among the most important monuments are the small theatre, a stoa, and the traces of a stadium. The theatre had a capacity of ca. 800-1000 spectators and has preserved also 14 citizenship-granting inscriptions, dating to the 3rd century B.C. The stoa was long 40m and 10m wide, being a simple one story building. Life in Nikaia ends abruptly in 167 B.C., when the army of Paulus Aemilus ravaged Epirus and parts of Southern Illyria.