Xi'an, called chang'an, pick Beijing, is the capital of shaanxi province, deputy provincial city, urban agglomerations in guanzhong plain core cities, important national center city in western China, the national important scientific research, education, industrial base. Xi'an is one of the four ancient capitals of China. It was designated by the United Nations educational, scientific and cultural organization (UNESCO) in 1981 as one of the world's top ten ancient capitals by the us media. Located in the middle of guanzhong plain, weihe river in the north, qinling mountains in the south, eight rivers run chang'an.