Introduction to the ancient city of Qinglong: The ancient city of Qinglong is located in the south of Qinglong County. It has a history of more than 500 years. In the fifteenth year of Hongwu in the Ming Dynasty (AD 1390), Annan Guard was established to guard Lian City (today's Qinglong City). County to town). In the 16th year of Kangxi's reign in the Qing Dynasty (1687), it was renamed Annan County in the form of stabilizing the south. With the rapid increase in population and the similarity in pronunciation with Vietnam, the National Government renamed Annan County Qinglong County in the 30th year of the Republic of China (1941).