Persepolis was the ceremonial capital of the Achaemenid Empire. It is situated in the plains of Marvdasht, encircled by southern Zagros mountains of Iran. Modern day Shiraz is situated 60 kilometres (37 mi) southwest of the ruins of Persepolis. The earliest remains of Persepolis date back to 515 BC. It exemplifies the Achaemenid style of architecture. UNESCO declared the ruins of Persepolis a World Heritage Site in 1979.