In ancient Iran there were many types of public structures, from among which one may mention the achievement represented by city walls. The twelfth to fourteenth century walls of Yazd, which are still standing, are perhaps the most interesting, imposing and skillfully planned. In Yazd, sections of the old walls and moat remain, providing an interesting example of a medieval wall, fortified by moat, towers and barbicans, now buried deep within a town which has long since expanded beyond its old limits. These walls were begun, it is said, in 1119 and rebuilt and extended during the 14th century. In places, they were 15 meters high; being nicely decorated with ornamental devices such as those employed on unglazed pottery.