Built in 1530 (the ninth year of the Ming-dynasty Jiajing Emperor’s reign), this was originally named the Taishen Hall but was given its current name eight years later upon being expanded and made a double-eave circular structure with a conical roof. In 1752 (the 17th year of the Qing-dynasty Qianlong Emperor’s reign), it was refurbished to its current state. It is the main hall of the Heavenly Warehouse of the Circular Mound Altar and was used in the worship of the God of Heaven and the emperor’s ancestors during the Heaven-worship ceremonies. The vault is 19.5 meters tall and has a diameter of 15.6 meters.