QIANXINAN, May 18 (Xinhua) -- An ancient city ruins resembles a footprint seen from above nestles at Pingzhai Village of Bouyei-Miao Autonomous Prefecture of Qianxinan, southwest China's Guizhou Province. Dating back to the Ming Dynasty (1368-1644), the site covers an area of about 18,000 square meters, with more than 900 meters of stone walls preserved.■