Founded more than 2,000 years ago, Suoyang City was an important landmark on the ancient Silk Road, and one which held a key role in the politics and the economy of the area during the Western Han Dynasty (206 BC-AD 24). Located in Guazhou county, Gansu, Suoyang Ruins is one of the largest and most well-preserved ancient sites in China with the city's defense structures still standing and its irrigation system in good condition.