One of Iran's World Heritage Sites inscribed by UNESCO, Takht-e Jamshid, known as "Persepolis", was the capital of the Achaemenid Empire. It was founded by Darius the Great (Darius I) in 518 BC. Persepolis is an outstanding and unique example of Achaemenid architecture, and it was the symbol of the Empire's might and culture. It was burned by the Greeks of Alexander the Great in 330 BC. According to Plutarch, they carried away its treasures on 20,000 mules and 5,000 camels.
If you have the chance to go on a trip to Fars Province in Iran, keep in mind that sightseeing Persepolis is a must and you can totally be sure that it has no equal in the world.