An ancient coin of the tumultuous Five Dynasties and Ten Kingdoms period (907-979) is displayed at the Ancient Coins Museum in Xiji County, northwest China's Ningxia Hui Autonomous Region, Oct. 10, 2012. Over 200,000 coins were collected in the museum. However the museum now faces challenges in the proper preservation of its coins as well as the growth of its collections. (Xinhua/Peng Zhaozhi)