© Provided by Xinhua YINCHUAN, June 16 (Xinhua) On a sand dune not far from a desert national park in Lingwu City of northwest China Ningxia Hui Aut
YINCHUAN, June 16 (Xinhua) On a sand dune not far from a desert national park in Lingwu City of northwest China Ningxia Hui Autonomous Region, workers of a f