Two-storeyed building which has 5 roams is at the back of the Hall of Frugality and placidity. There are no stairs. You should go up through the terrace of the east rockery. It has woods, hill, mist and waters. In the morning is fog, at sunset is cloud. So it was named 'Hall of Yunshan shengdi' by Emperor Kangxi. This is the place where empresses and imperial concubine offered a sacrifice to the Moan to pray for happiness, and emperors and their wives enjoyed the sight of the Moon.