It takes roughly an hour to drive from Khiva to Biruniy and a further hour to get to Ayaz

Sue standing by the vaulted corridor between the inner and outer walls of Ayaz qala 1 on a freezing March day in 2002.

The outer walls were reinforced during the 3rd century BC by the addition of 45 regularly spaced semi-elliptical watch towers, the towers on the eastern and western sides being shorter than those on the northern side. We know they are additions because they were not bonded into the outer wall. 

The western flank of Ayaz qala 1 showing the crumbling semi-elliptical watch towers.

Access to the fort was gained by means of a labyrinth entrance, located on the southern flank of the fort. Visitors approached the fort along this flank, overlooked by defenders. They first passed through a massive gateway supported by two projecting rectangular towers and entered a small rectangular holding chamber, where they could be inspected while being covered by surrounding archers. Once accepted they were forced to turn right to enter the gate of the main refuge. The inside of the fort was completely devoid of permanent buildings although there may have been a central cistern for storing rain water.