The Temple of Heaven in the southern part of Beijing is China's largest existing complex of ancient sacrificial buildings. Occupying an area of 273 hectares, it is three times the area of the Forbidden City. It was built in 1420 for emperors to worship Heaven. The principle buildings include the Altar of Prayer for Good Harvests, Imperial Vault of Heaven and Circular Mound Altar.
The Altar of Prayer for Good Harvest, 38 meters in height and 30 meters in diameter, stands on a round foundation built with three levels of marble stones. This towering triple-eave hall is under a three-story, cone-shaped glaze-tile roof in blue color crowned with a gilded knob. A circular wall of polished bricks known as the Echo Wall encloses the Imperial Vault of Heaven. The Circular Mount Altar, south to the Imperial Vault of Heaven, is where the emperor prayed to heaven. At the center lies a round stone called the Center of Heaven Stone that echoes when a visitor speaks loudly when standing on the stone.
