The Mã Pí Lèng Pass is a mountain pass about 20 kilometers long that connects the towns of Vng Văn and Mèo Vạc. It is located at an altitude of 1,500m, and the road around Ma Pi Leng was first built by the Yao, H'mong, Tay and Lolo minorities. Ma Pi Leng Pass is not long but it is the most dangerous pass in the north border area, in fact it is regarded as the "King" of Vietnam pass or Great Wall of Vietnam. At the top of Ma Pi Leng Mountain is the "happiness" road, which is a stone stele that records signs in the construction process.