Tacht-e Suleiman

The Tacht-e Suleiman building complex in the north of Iran consists of a palace, a Zoroastrian fire temple and fortifications from the late Sassanid period (about 420-640 AD).
The whole complex was built around a spring pot, which has a diameter of approx. 100 metres and is 112 metres deep.
The spring water emerges at a constant temperature of 21 degrees Celsius and is very calcareous, so that in the course of the millennia an elevation of about 50 meters was formed, whereupon the plant was erected. 
In the 6th century AD the Zoroastrian fire sanctuary Atur Guschnasp was moved here. The fire temple of the empire was visited by the Sassanid Persian kings, e.g. after the enthronement or before larger battles, in order to accomplish religious ceremonies.
After the end of the Sassanid Empire the fire cult was continued until the 10th century.
In the 13th century, Ilchan Abaqa Chan had a hunting lodge built over the temple complex.
2003 Tacht-e Suleiman became a UNESCO world heritage site.