At the edge of the Mu Us Desert, a thousand-year-old castle lies beside the Wuding River. It is called Boluo ancient castle, which is 25 kilometers northeast of Hengshan County, Yunlin City, northwest China's Shaanxi Province.

Boluo is a Buddhist term, it is the transliteration of "reach the other side" in Sanskrit. Boluo castle is one of the 36 key pass castles of Ming Great Wall. Built in Sui Dynasty, the castle has a history of over 1,400 years. It has experienced large-scale enlargements and renovations since it was built. The castle was once an important political, economic and cultural center in its peak period, and was regarded as "little Yangzhou" or "little Beijing".

In 1992, Boluo ancient castle was listed as one of the province-level cultural relic protection units. [China.org.cn/Photo by You Bing]