4. The road network of Erlitou site, Luoyang, Henan province, from the 18th to 16th century BC

Erlitou site was first found in 1959 and is thought to cover 3 square kilometers. It is home to a palatial architectural compound, national-level workshops for bronze ware, and a graveyard for nobles. Research over the recent decades indicated the site to be the last capital city of the Xia Dynasty (c. 21st century-16th century BC), the first united central dynasty recorded in Chinese history.

Thanks to the crisscrossing road network, which was newly unearthed, the city was separated into grids with various functional domains. The roads near the palace area were found to be 18 meters wide, and in some sections of the city, they were also walled.

Discovery of lacquered pottery also filled some gaps in handicraft studies in the region.

This rigidly designed urban layout of a capital city laid a crucial foundation for national systems and civilizations in later periods. It also provided references for the exploration of other city ruins from subsequent centuries.