Introduction to the Hanging Wall: Located 8 kilometers north of Jiayuguan City, on the northern slope of Heishan Mountain to the north of the Shiguan Gorge, it is part of the Jiayuguan Military Defense System. It was first built in the 18th year of the Jiajing reign of the Ming Dynasty (1539). It was originally 1.5 kilometers long and was a stone-filled earth wall. The existing Great Wall is 750 meters long, of which 231 meters are made of loess rammed city wall climbing 150 meters high and with an inclination of 45 degrees. On the ridge, it looks like the Great Wall hanging upside down, with iron walls hanging in the air, falling steeply from the mountain, blocking the entrance of Shiguan Gorge.