The Angka-kala settlement (I–III centuries, X–XII centuries A.D.) is situated 22 kilometres north of Turtkul city.

The Fortress is well preserved and has an almost square form in the architectural plan. Here you can still see a corridor formed by the outer and inner walls, rectangular towers, loopholes shaped for shooting that are cut through the exterior wall, and towers in a single line. It is noteworthy that almost all the bricks overlapping the loopholes are marked with tamga – a sign of a master. An ancient Khorezm inscription found on one of the bricks consists of five characters engraved in a single line.

The monument belongs to the late antiquity culture of Khorezm (I–III centuries A.D.). The extant ceramics found in the Fortress date back to this period. However, the well-preserved fortified constructions were probably used during the Middle Ages (X–XII centuries).