Imperial Vault of Heaven

　　Located in the Temple of Heaven. It is the place where the plaques of the Heavenly Emperor and the eight preceding generations of emperors are enshrined.

　　The Imperial Vault of Heaven was built in the ninth year of the Jiajing reign of the Ming Dynasty (1530). Initially, it was a double-eaved circular building named the "Hall of the Supreme God." It served as the main hall of the Circular Mound Altar, used for enshrining the divine tablets during daily worship ceremonies. In the seventeenth year of the Jiajing reign (1538), it was renamed the "Imperial Vault of Heaven." In the seventeenth year of the Qianlong reign of the Qing Dynasty (1752), it was reconstructed into its current form. The hall is 19.5 meters high and 15.6 meters in diameter, featuring a wooden arch structure with eight eaves posts and eight golden posts. It has a south-facing entrance, latticed doors and windows with diamond-patterned panes, blue-glazed railing walls, and walls on the east, west, and north sides made entirely of finely laid bricks up to the top. Inside the hall, there is a round domed ceiling, with a central golden coiled dragon caisson ceiling and a double-dragon ceiling adorned in gold. The golden posts are decorated with golden entwined lotus patterns, and both the interior and exterior are painted with golden dragon and imperial seal designs. At the center of the hall stands a circular stone Sumeru pedestal with raised front and upturned corners at the back, 1.51 meters high and 2.53 meters in diameter. The structure is precise and exquisite, topped with a blue-tiled golden roof, elegant and solemn. The ceiling features an openwork caisson in green tones with golden dragons, centered around a large golden coiled dragon motif, making it a masterpiece of ancient architecture. The surrounding circular wall functions acoustically as a sound transmission wall, hence it is also called the Echo Wall.

　　The Imperial Vault of Heaven is located to the north of the Circular Mound Altar and serves as the site for enshrining the spirit tablets used in the sacrifices held at the altar. It currently has a single-eaved, blue-tiled, round pyramidal roof crowned with a gilded finial. The hall is constructed of brick and wood, with no internal beams; the roof is supported entirely by eight eaves posts, eight golden posts, and a complex system of brackets, ingeniously utilizing mechanical principles. The three-tiered caisson ceiling gradually converges upward, making it quite unique and rarely seen in ancient architecture. The eaves are covered with blue-glazed tiles, and the roof is topped with a gilded finial. The hall’s walls are perfectly round, constructed from meticulously laid bricks, resembling a giant sapphire umbrella with a golden finial when viewed from afar. Flanking the main hall are two side halls, each five bays wide, with a single-eaved hip-and-gable roof. Outside the main hall are the famous Echo Wall, the Three Echo Stones, and the Dialogue Stone.

　　The enclosing wall of the Imperial Vault of Heaven has sound-transmitting properties, commonly known as the Echo Wall. Historically, the acoustic effect of the wall puzzled many, as the phenomenon could not be scientifically explained for a long time. In 1953, Professor Tang Dingyuan conducted tests on the acoustics of the Imperial Vault of Heaven and concluded that the wall's dense structure and smooth surface prevented sound waves from being absorbed, causing them to reflect instead. This created the echo effect and formed a unique acoustic phenomenon. This was the first scientific explanation of the echo effects observed in the various buildings of the Temple of Heaven.

Temple of Heaven Park

Circular Mound Altar

Divine Music Administration

Hall of Imperial Zenith

Sacred Way

Hall of Prayer for Good Harvests

Echo Wall of the Temple of Heaven