A relief in Persepolis shows iris flowers and their underground rhizomes and connection, as a Zorostrian symbol of protection and preservation of life. Persepolis is a 2500-year old World Heritage Site of ancient Persian palaces and temples near Shiraz in southern Iran. It was the ceremonial capital of the Persian Empire during the Achaemenid dynasty. At the height of its power, the Achaemenid Empire encompassed about 7.7 million square kilometers and spanned three continents, as far west as Libya to nearly all Middle East, and to Central Asia.