The city walls are a rare example of medieval fortification, which survived to our time. Khiva was surrounded by two rows of walls – Ichan-Kala (inner town) and Dishan Kala (outer city). Ichan-Kala walls were built between 5th and 4th century BC, they were above the level of the walls of Dishan-Kala, possibly due to the natural relief (according to legend, the city was built on a sandy hill).
The city walls were built of sun-dried bricks (40x40x10 cm), and during centuries they were rebuilt several times. The walls of Ichan-Kala are 8-10 meters in height, 6-8 meters wide and 2250 meters long. On every 30 meters there is a round defensive tower, bulging beyond the walls of Ichan-Kala. On top of the walls and towers there are toothed railings with narrow loopholes, to repel the enemy attacks during the siege.
In the system of fortifications there were ditches filled with water; even now it can be seen on a relief in the south part, and the north and west asphalt covered the old ditches.
Dishan-Kala walls were built by Allah Kuli Khan in 1842. It is interesting from where much clay was taken to build walls. Studies have shown that the clay was mined from two kilometres north of the city, in an area called Govuk-Kul; now there is a large lake there. And today, as always the high quality local clay is used by modern potters. Legend says, that when the Prophet Muhammad built the Medina, the clay from these places was used, and a lake appeared later is considered to be holy.
The city gates were also part of the defence system. They have special equipment, used by guards, guarding the city: on both sides of the arched passage there are “hit” towers, and above the gate there is a viewing gallery. The passage is covered with arched roof (Koy Darwaza) or, if the corridor is too long, with several domes.