The Neolithic Hongshan Culture is an aboriginal culture that existed in north China about 6,000 years ago. The culture is named after Hongshanhou, a site in Hongshan District, Hongshan District, Chifeng. The Hongshanhou site was discovered by a Japanese archaeologist in 1908 and extensively excavated in 1935. The archaeological site at Niuheliang is a unique ritual complex associated with the Hongshan culture. There excavators discovered an underground temple complex -- which included an altar. Over 60 nearby tombs were unearthed, all constructed of stone and covered by stone mounds, frequently including jade artifacts. Cairns were discovered atop two nearby hills, with either round or square stepped tombs, made of piled limestone. Entombed inside were sculptures of dragons and tortoises. It was suggested religious sacrifice might have been performed within the Hongshan culture.The Hongshan employed advanced jade shaping and carving tools that may have been made from meteorite iron. One fascinating study is the evidence of high content iron found in black jades used for ritual objects by the early Hongshan. Many of these artifacts are magnetic and express the possibility that the Hongshan were aware of magnetic earth forces. Another fascinating observation through the study of Hongshan jade artifacts is the abundance of "alien" like motifs and figurines that are completely unexplainable as they are not found in other Neolithic cultures. From the study of Hongshan artifacts, a highly sophisticated knowledge of mathematics and astronomy become evident. Hongshan burial artifacts include some of the earliest known examples of jade work. The Hongshan culture is known for its jade pig dragons and embryo dragons. Clay figurines, including figurines of pregnant women, are also found throughout Hongshan sites.From: http://en.wikipedia.org/wiki/Hongshan_culture; http://www.thejaderoad.com/hongshan.html; http://english.peopledaily.com.cn/90001/90782/90873/7091686.html