The Imperial Vault of Heaven in Temple of Heaven Park
Enclosing the Imperial Vault of Heaven is a grey wall covered with blue glazed tiles, which are 3.27 meters high and 193.2 meters long. It is the most wonderful part of the complex and known as the Echo Wall. Constructed with smooth and solid bricks, the wall enables a whisper to travel clearly from one end to the other, hence the name. This indicates that Chinese people had known how to apply the acoustic theory into buildings at the time.
Flanking Imperial Vault of Heaven are eastern and western secondary halls. Covered by blue tiles, these two halls have gray walls and beams resting on the gables. Tablets of Matching Gods, such as God of the Sun, Moon, Stars, Wind, Thunder, Rain, Clouds, and so on, were enshrined here after worshipping ceremonies.