An aerial photo taken on Aug. 31, 2017 shows buildings inside walls of Yongtai ancient city in Jingtai County, northwest China's Gansu Province. Located 25 kilometers of Jingtai County, Yongtai Turtle Town got its name because of the turtle-shape of the castle. As an ancient town dated back to the Ming Dynasty (1368-1644), the town was preserved as a national-level cultural relic. (Xinhua/Fan Peishen)