Bas-reliefs at Persepolis, southern Iran. A 2500-year old World Heritage Site of ancient Persian palaces and temples, Persepolis 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.