Guldursun, Southern Karakalpakstan, Uzbekistan
Major Guldursun is one of the largest fortresses of ancient Khorezm (350x230m), it is almost twice as big as the Major Kyrk Kyz Kala by area. In the base of Major Guldursun fortress were found elements of fortification systems dated from the 4th–3rd centuries BC to 4th century AD. The modern walls and towers were built during Khorezmshakhs in the 12th century on the place of abandoned ancient fortress. It is known that Major Guldursun was conquered by Mongols in 1220 but was not destroyed. Almost the whole contour of the walls approx. 15 m high is preserved.
The only access to the fortress with the gate labyrinth is on the eastern side. The line of protective walls is situated approx. 18m from the exterior walls, so that the towers, probably, were connected with the fortress by bridges.