Chogha Zanbil is an ancient Elamite complex in Khuzestan province of Iran. It was built about 1250 BC by the king Untash-Napirisha. Chogha Zanbil is considered to be the best preserved example of the stepped pyramidal monument by UNESCO. In 1979, Chogha Zanbil became the first Iranian site to be inscribed on the UNESCO World Heritage List.