The Big Guldursun (IV–III centuries B.C. – III century A.D., XII–XIII centuries A.D.) is one of the most splendid monuments of the Khorezm Shahs Dynasty. It is one of the largest Ancient Khorezm fortresses.
The Big Guldursun has an irregular rectangular shape with an area of 80,500 square metres (350 × 230 metres). The monument’s corners are oriented to the cardinal points. The Fortress entrance is located in the middle of the eastern wall.
Antique walls and towers in the pedimental parts of ramparts are built of rammed clay. The remaining parts are decorated with earth bricks. The walls have been preserved in their full height, sometimes reaching 15 metres. Later in the XII–XIII centuries they were rebuilt by Khorezm Shahs. The Fortress fortification was reinforced by an outer barrier construction with a second row of projecting towers.
It is assumed that medieval fortresses were used mainly as strategic facilities, since at that time they were not used as residential areas. A great number of antique and medieval ceramics, bronze handicrafts and jewellery, and ancient and medieval coins were found there during excavations. Based on the findings of the coins it was concluded that the last period of the Big Guldursun habitation was 1220, the era of the Mohammed Khorezm Shah reign, when Khorezm was invaded by Mongolian troops.
The grand ruins of the Big Guldursun are stepped in legends and stories. Not long ago there was a popular belief that the Fortress hides an underground passage protected by a ferocious dragon. If a person tries to go in search of the Guldursun treasures, he will suffer a great misfortune.