To cater to the preferences and tastes of five Qing emperors, the renovations and alterations of the Old Summer Palace went on and off for more than 100 of years. (1) Shangxia Tianguang (Heavenly Light Above and Below) was a two-layer building beside Back Lake, with a corridor bridge winding across on the water in front of it. (2) Midterm of Qianlong’s reign, the corridor bridge became entirely symmetrical in shape and the pavilions on its two side were identical. While in the reign of the Daoguang Emperor, huge changes came to this scenic spot. (3) The corridor bridge disappeared completely and the main building was changed to a Jiangnan-style building. (4) During the reign of the Xianfeng Emperor, a large sunshade was added to the façade of the building.