The ancient province of Fars in southern Iran was the home of a number of capital cities over several dynasties. The present article introduces archaeological monuments known as tal-e khandaghs, so named because of the presence of a deep moat that invariably surrounds a substantial rampart. The tal-e khandagh at Sar Mashhad, which Trümpelmann interpreted as a tower of silence, is the earliest of these structures. In a survey carried out in 2007 between Bishapur, Borazjan, and Firouzabad, the author identified and studied a number of similar structures and came to the conclusion that they probably functioned as defensive military installations.