This frustum was built in the 18th year of the Jiajing Period of the Ming Dynasty (1539). With a flat top, it is a square pyramid, with a length, width, and height of each 14 meters. As the result of water erosion over hundreds of years, some parts have been destroyed. Standing alongside a cliff, the frustum shows its age. To preserve the precious relic, the Jiayuguan city government has built a 30-meter-long arched fortification, which creates a secondary structure and functions as an enclosure. Standing on the tower, visitors can experience the grandeur of an ancient civilization while appreciating the marvelous view in this place. 

7 kilometers south of Jiayuguan(嘉峪关Jiāyùguān) City lies the Great Wall’s first fire tower(烽火台Fēnghuŏtái), regarded by some as the world’s first frustum(a truncated cone or pyramid; the part that is left when a cone or pyramid is cut by a plane parallel to the base and the apical part is removed), or cut-off pyramid(a polyhedron having a polygonal base and triangular sides with a common vertex). This structure marks the western beginning of the Ming Great Wall.