Iran - 25 Rials 2500th Anniversary of Persia - 1971

This is part of a beautiful series of proof coins celebrating the 2500 Anniversary of the Persian Empire. This one depicts a figure of what appears to be back to back bulls atop a column. This column is at the Palace of Artaxerxes at Susa. This one year type had a mintage of 18,000.
Other info says: Capital of a column from the audience hall of the palace of Darius I, Susa, c. 510 B.C.E., Achaemenid, Tell of the Apadana, Susa, Iran (Louvre).