Darius the Great built the greatest palace at Persepolis on the western side. This palace was called the Apadana and was used for official audiences.
The work began in 515 BC and was completed 30 years later by his son Xerxes I.
The palace had a grand hall in the shape of a square, each side 60 metres (200 ft) long with 72 columns (each 24 metres tall), thirteen of which still stand on the enormous platform.