Detail of roof tile from the Temple of Heaven in southern Beijing. Built in 1420, the templeâ€™s numerous buildings and surrounding grounds are larger than the Forbidden City. Here, emperors of the Ming and Qing dynasties came at the winter solstice and the first spring moon to pray for a bountiful harvest. If there was a summer drought, a third visit was sometimes required. (Common people were not permitted to witness any of these ceremonies.) The roof of the Hall of Prayer for Good Harvest is glazed with 50,000 tiles like this one. Their distinctive dark blue color and round ends â€“ as well as the round shape of the hall itself â€“ symbolize the heavens. The earth is represented by the square base of the building. The dragon on the end of each tile is the emperorâ€™s symbol.