Tiantan, World Cultural Heritage, National Key Cultural Relics Protection Unit, National AAAAA Tourist Scenic Spot, National Civilized Scenic Spot Demonstration Site. Tiantan, south of Beijing, east of Yongding Mennei Street, Dongcheng District. It covers an area of about 2.73 million square meters. The Temple of Heaven was first built in the eighteenth year of Yongle in the Ming Dynasty (1420), and was reconstructed in the reign of Qianlong and Guangxu in the Qing Dynasty. For the emperors of Ming and Qing dynasties to worship the emperor's heaven and pray for a place full of grain. The Temple of Heaven is the general name of the two altars of Qiqiu and Qigu. It has two walls, which form the inner and outer altars. The South and North circles of the altar wall symbolize the place of the heavenly circle. The main building is the inner altar. The Qiqiu altar is in the South and the Qigu altar is in the north. The two altars are on the same north-south axis with walls separated in the middle. The main buildings in the mound are mound mound, emperor dome and so on. The main buildings in the prayer Valley altar are prayer hall, emperor Qian hall, prayer gate, etc.