Archaeologists work at an excavation site in the Pingliangtai Ancient City ruins in central China's Henan Province. (Photo provided to China News Service)
A number of pottery drain pipes at a Neolithic site of Longshan Culture dating back more than 4,000 years has been discovered in Henan. It is China's earliest and most complete urban drainage system.
A graphic of the excavation site in the Pingliangtai Ancient City ruins in central China's Henan Province. (Photo provided to China News Service)
A graphic of the excavation site in the Pingliangtai Ancient City ruins in central China's Henan Province. (Photo provided to China News Service)
Pottery drain pipes are excavated in the Pingliangtai Ancient City ruins in central China's Henan Province. (Photo provided to China News Service)