With an area of 1120 m², this edifice was built in the early 20th century in the form of the letter 王 (meaning "king" in English). This is not only a historical relic but also a fabulous architectural landmark of local ethnic groups. This edifice is also a destination always interested many visitors. Located at 1600 m at height compare to sea level, with area of 1120 m². Vuong dynasty area is an edifice and fortress of Vuong clan in Dong Van. Vuong King (Vuong Chinh Duc) became rich from dealing goods, especially opium. Sa Phin is the middle point of opium from the Golden Triangle region of Myanmar Yunnan China to Indochina. Duc also set up his own army unit of loyal Hmong people and equipped them with weapons. The building was built at the beginning of 20th century, imitating Chinese ancient architect of Man Thanh dynasty and being carved skillfully in Hoa Nam style. The building is used for the purpose of edifice, fortress, residence, working, visitor receiving. It is a symbol of Hmong prosperity, and the talent of the war strategy, feng shei location and traditional culture. By motorbike or car.