Photo taken on Aug 10, 2017 shows the excavation site of Xinzheng Gate in Kaifeng city, Central China's Henan province. Six ancient cities dating from the Warring States Period (475 BC- 221 BC) 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. [Photo/Xinhua]