Phra Wihan Sung, or Ho Phra Sung, is an important historical site located just outside the ancient city wall to the north in the area of Sanam Na Muang, on Ratchadamnoen Road. The site is so called because of its high location on a hill, 2.10 metres above level ground. There is no exact historical evidence but it is believed that its architecture and wall murals are from the early Rattanakosin period. The building houses plaster images with a thick, clay core. The images are either from the 18th-19th century or from the late Ayutthaya period.