Ming Tombs are located at Chan Ping County, 31 miles northwest of Beijing. Of the 16 emperors who ruled China during the Ming Dynasty (1368-1644), 13 are buried in elaborate complexes in the valley of the Ming Tombs north of Beijing. Tomb construction began here in 1409 and continued for 2 centuries. The valley was sealed off by a red gate at its only entrance, guards were posted to keep out the people, and no one, not even the emperor, could ride a horse on these grounds. The site of this huge cemetery was chosen by the same emperor, Yongle, who oversaw the construction of the Forbidden City. The tombs reflect a similar conception of Imperial architecture, consisting of walls, gates, courtyards, stairways, and elaborate pavilions with roofs of yellow tiles (yellow being the color of emperors). The actual burial chamber (a tumulus) is underground. The emperor, his wife, and his favored concubines were the only people buried there, along with enough royal treasure to stuff a small museum. The mausoleums have been perfectly preserved, as has the necropolis of each of the many emperors. Because of its long history, palatial and integrated architecture, the site has a high cultural and historic value.