The rectangular enclosure in th distance is th modern Zoroastrian cemetery. The domed buildings functioned as accommodation for the relatives of the dead who i presume remained there until all the necessary ceremonies were completed. The city of Yazd is in the distance.
Inside the tower. The dead were placed in consecutive circles with children, women and men forming the three circles. When the bones were "clean", they were placed inside the pit and left to the elements. I pity the men whose job was to tend to these matters.