4. The Zhouyuan Site in Baoji, Shaanxi province

In recent years, the archaeological explorations of the Zhouyuan Site have focused on looking for the wall systems and large-scale buildings to further reveal the settlement structure of the Shang (c. 16th century-11th century BC) and Zhou (c. 11th century-256 BC) periods. As of now, a large rammed earth complex from before the Zhou Dynasty has been discovered, as well as the triple city walls of the palace city, small city, and large city from the Western Zhou period (c.11th century-771 BC). The discovery of the large complex provides key evidence for determining that the site was a pre-Zhou urban center before the downfall of the Shang dynasty. The discovery of the triple city walls at Zhouyuan not only advances our understanding of the form and nature of the Zhouyuan settlement but also provides indispensable research materials for the history of urban development in China.