Criterion (iii): The historic city of Yazd bears witness to an exceptionally elaborate construction system in earthen architecture and the adaptation of the ways of living to hostile environment for several millennia. AuthenticityBeing a living dynamic city, Yazd has evolved gradually with some inevitable changes. Also a large part of the historic city is still inhabited (with a rate of 80% private ownership). A part of the University of Yazd has been established in the historic city. Guidelines for the use, maintenance and conservation of earthen historic buildings, with attention to interiors, should be elaborated in order to assist private owners of historic buildings.