Archaeologists have unearthed a number of pottery drain pipes at a Neolithic site of Longshan Culture dating back more than 4,000 years and believe they form China's earliest and most complete urban drainage system. The city drainage system was excavated in the Pingliangtai Ancient City ruins in central China's Henan Province. "The pottery pipes were connected with drainage ditches in the city," said Cao Yanpeng, associate research fellow with the Henan Provincial Institute of Cultural Relics and Archaeology. The development of public facilities and productivity are key indicators to measure the level of civilization in society. The discovery is of...