View of prehistoric site Shimao ruins in NW China

Shimao ruins, located in Shenmu of Northwest China's Shaanxi province, were a neolithic city built about 4,300 years ago and abandoned roughly 300 years later during the Xia Dynasty (2070-1600 BC), the first dynasty in China described in historical chronicles.

Over the past 10 years, excavators have uncovered a stone city with immense fortifications and sophisticated infrastructure, thousands of luxurious artifacts and a 230-foot-high stepped pyramid.

"The site's early date and peripheral location were surprising since Chinese civilization was thought to have first developed in the Central Plains around 500 years after Shimao's founding," read an article in the Archaeology journal.