Xi’an is located in the Guanzhong basin of the center of the Yellow River area. It’s called one of the biggest ancient capitals of the world ,including Athens,Rome and Cairo.From 11th century B.C. to the 10th century, there are thirteen dynastys or regimes which founded their capital or regime early or late in Xi’an, which took more than 1100 years.In 1981,the UNESCO identified Xi’an as a famous historical city of the world.