The Fire Altars
Twin fire altars facing the plain of Marvdasht, can be seen if you walk round the hillside in the same direction that you came. They command a fine view over the latter plain. In the hollowed-out tops of these altars the holy fire was kindled. They are cut from the living rock round the corner of the cliff containing the tombs of four Achaemeni.an Kings. The old Achaemenian highway, on which they are positioned, runs from Istakhr past the tombs and the table mountains visible in the north, to Susa. The fire altars might have doubled as beacons and lighthouses for the traveler approaching at night.
Between these fire altars and the investiture scene of Ardeshir I, is the old stone quarry. Rock next to the carving of Ardeshir's investiture is split which permitted water to cascade down in front of the carving. The water was brought by a water course, wh.ich was carved out of the rock underneath the stone quarries.