Introduction to Chengguang Hall: Chengguang Hall is the main building of Tuancheng. It was first built in the Ming Dynasty. It was originally a round hall and was changed to a square shape when it was rebuilt in the 29th year of Kangxi reign of the Qing Dynasty (1690 AD). The main hall faces south from the north, with double eaves on the top of the mountain. There are single-eaves rolling sheds surrounding the building, making the hall appear in the shape of a dog-eared cross. It is said to have "nine beams, eighteen columns and seventy-two ridges", which looks like the turrets of the Forbidden City. Just as exquisite and skillful. The roof of the hall is covered with yellow glazed tiles, with green trim and raised cornices. In the center of the hall, there are four huge wellhead pillars. The round light on the wellhead ceiling is like two dragons playing with pearls, and the corners are painted with cranes. There are couplets on the pillars. The plaque above reads "Big Round Treasure Mirror"