Visitors go on a sightseeing tour around the ruins of Suoyang city in Guazhou county, Northwest China's Gansu province, Jan 22, 2015. Suoyang, which dates back to the Han Dynasty (202 BC-220 AD), was an ancient city on the Silk Road. It was added to the UNESCO World Heritage list in last June, together with 32 other historical sites on the Silk Road, a legendry Eurasian cultural communication and trade route. [Photo/Xinhua]