Persepolis
Darius I built the greatest palace at Persepolis on the western side of platform. This palace was called the "Apadana". The King of Kings used it for official audiences. The work began in 518 BC, and his son, Xerxes I, completed it 30 years later. The palace had a grand hall in the shape of a square, each side long with seventy-two columns, thirteen of which still stand on the enormous platform. Each column is high with a square Taurus (bull) and plinth. The columns carried the weight of the vast and heavy ceiling. The tops of the columns were made from animal sculptures such as two-headed lions, eagles, human beings and cows (cows were symbols of fertility and abundance in ancient Iran). The columns were joined to each other with the help of oak and cedar beams, which were brought from Lebanon. The walls were covered with a layer of mud and stucco to a depth of 5 cm, which was used for bonding, and then covered with the greenish stucco which is found throughout the palaces.
Serraepolis
It was a colony from eastern Macedonia whose metropolis was Siris (modern Serres), and after which it was named. It was located 150 "stadia" from another Macedonian colony called Aegeae (modern Yumurtalık) and 250 "stadia" from Antioch (modern Antakya). Although the exact foundation time of the city is unknown, it would be safe to assume that it was either established by refugees from Paeonia, forcibly resettled by the Persian general Megabazus in 486 B.C., or established during the Hellenistic period by colonists from Siris that followed Alexander the Great and the Seleucids.