The Altar of Earth, located east of Andingmen Gate, was constructed for the worship of Earth in the Northern City in 1530 during the reign of Emperor Jiajing of the Ming Dynasty. Extending over an area of 37 hectares, it was surrounded by a double square enclosure. The outer enclosure no longer stands but its west gate remains. The square altar, representing the earth, is made of two tiers of marble, each two meters high. The number nine stood for Heaven and the number six for Earth; the upper tier of the altar measures 20 square meters and the lower tier is 22 square meters.
The largest structure in the Altar of Earth is the altar known as Fangzetan - so called because a moat surrounds it. A sculpted stone dragon head is fixed on the west side of the southwestern corner of the moat wall; water was brought from a well through the dragon head. Fangzetan was built on a north-south axis, and it is surrounded by two square enclosures, both painted red and surmounted with yellow glazed tiles. Both Inner and outer enclosures have triple white marble gates to the north and one gate to the east, south and west.
The ceremonies for worshipping the Earth took place once a year, at the summer solstice. On important occasions such as an emperor's coronation, birthday, marriage or funeral, a representative of the emperor would come to "report" to the God of Earth. The Altar of Earth was no longer used after the overthrow of the Qing Dynasty in 1911; it became a public park in 1925. It was once badly plundered and, because of years of neglect, became a wilderness choked with head-high weeds. The People's Government gave the Altar of Earth a new look in 1957, when it was once more turned into a park. The buildings were repaired and an orchard built as well as a large number of trees and flowers were planted.