Located on the east side outside the Zhengyang Gate, the Temple of Heaven was used as a site by emperors of the Ming and Qing dynasties to offer sacrifice to heaven and pray for bumper harvests. The northern part of the Temple of Heaven is semicircular while the southern part is square, a pattern representing the ancient belief that "Heaven is round and Earth square". Surrounded by a double wall, and covering an area of 273 hectares, it is divided into the Inner Temple and the Outer Temple by the double wall. Main buildings are concentrated in the Inner Temple. As a masterpiece of building techniques of Ming and Qing dynasties, the Temple of Heaven is a precious ancient architecture and the world's largest building complex for offering sacrifice to heaven.