An important Paleolithic site, this site was first excavated in 1927, in a cave on Dragon Bone Hill at Zhoukoudian, southwest of Beijing. In 1929, skull fossils of Peking Man were discovered here, providing concrete evidence for the existence of primitive man in the Beijing area 500,000 years ago and marking a milestone in the history of paleo-anthropology. So far, a total of 6 skulls, a great deal of stone crafts and the remains of using fire have been excavated, providing concrete data for the study of the evolution of pre-historic biology and the development of pre-historic culture. The Peking Man Site at Zhoukoudian was included in the UNESCO World Cultural Heritage List in 1987.