Guldursun-Kala

Guldursun-Kala, also Guldursun Qala, in modern Karakalpakstan, Uzbekistan, was an ancient fortress in Chorasmia built in the 12th century CE. It is one of the largest fortresses of Khwarezm, with perimeter walls of about 1 kilometer in total length, and an internal area of about 6.4 hectares.

Source: Wikipedia (CC BY-SA 4.0) — https://en.wikipedia.org/wiki/Guldursun-Kala