A building with a dome over a rock at the highest point of Niasar village. This is the same Chahar Taghi that has remained intact since the time of Sassanid dynasty (224-651 CE).
It is a 14 by 14 meter building which contains a chamber with a dome over it. There are no walls on the four sides of the chamber and has been made of stones put together with a mortar of plaster.
There are two theories about the building purpose; the first idea implies that the building was a Zoroastrian Fire Temple. Based on this idea, as the fire over the Niasar temple could be seen from distance, the building might have had a symbolic role.
Second theory which was deeply investigated in 2001, implies that such a building was an ancient observatory. The structure of the building from calendar point of view is so that at start and middle of each season, early sun rays when observed through columns, form a unique and precise configuration. This phenomenon makes the building a highly accurate solar calendar.
The green and beautiful resort village of Niasar is located 28 kilometers west of Kashan, Iran.