Beijing was the largest city in the world by population for much of the second millennium A. Beijing has seven UNESCO World Heritage Sites – the Forbidden City, Temple of Heaven, Summer Palace, Ming Tombs, Zhoukoudian, as well as parts of the Great Wall and the Grand Canal, all popular locations for tourism.
Siheyuans, the city's traditional housing style, and hutongs, the narrow alleys between siheyuans, are major tourist attractions and are common in urban Beijing.
The earliest traces of human habitation in the Beijing municipality were found in the caves of Dragon Bone Hill near the village of Zhoukoudian in Fangshan District, where Peking Man lived.
Homo erectus fossils from the caves date to 230,000 to 250,000 years ago.
Under the Tang Dynasty, Beijing as Fanyang, served as a military frontier command center.