Photo taken on Aug. 10, 2017 shows an archaeological site of Xinzheng Gate in Kaifeng City, central China's Henan Province. Six ancient cities dating from the Warring States Period (475 B.C.- 221 B.C.) to the Qing Dynasty (1644-1911) were found deep underground in Kaifeng. The city launched a "City upon a City" Xinzheng Gate site project to carry out archaeological excavation here in 2012. (Xinhua/Zhu Xiang)