In southwestern Iran, roughly 650 km (400 mi) south of the capital city of Tehran, and some 70 km (40 mi) northeast of Shiraz, a cultivated plain gives way to the Zagros Mountains. At the transition between flat land and rugged mountain, at the base of Kuh-i-Rahmat, or "Mountain of Mercy," lies Persepolis. Founded around 518 B.C. by Darius the Great, the site served as the ceremonial capital of the Achaemenid (or Persian) Empire. Image courtesy of NASA.