About seven kilometers south of Jiayuguan City lies in the Great Wall's first fire tower, regarded by some as the world's first frustum, or cut-off pyramid. This structure marks the western beginning of the Ming Great Wall.
 
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 its length, width, and height 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 of the vast Gobi.