Apadana Palace in Susa, which is undoubtedly one of the landmarks of Khuzestan Province, was built on the remains of Elamite by the order of Darius the Great Achaemenid king of about 515_521 BC. This palace was the palace of the Achaemenid kings. Apadana is not the name of a castle, but the ancient name of the buildings known as pillars. You can see the best examples of Apadana in Persepolis and Shosh Palace.
Palace of Darius