The ancient city on the Silk Road - the ancient city of Octagonal in the early morning, the quiet Ganjia grassland... The village residence on the Ganjia grassland... The ancient city site of Octagonal is located 24 kilometers northeast of Xiahe County, Gansu Province, on the south side of Baishiya and the north bank of Yangqu. The Han Dynasty once set up Baishi County here, anciently as a military transportation point. According to the examination, it may be the Tang Dynasty carved nest city, the Song Dynasty a public city. The ancient Octagon City is a hollow cross-shaped city, commonly known as "Karang" in Tibetan, and the Tibetan history book is called "Karl Ngzhong", meaning the city of thousands of characters. There are eight piers on each corner of the cross city, forming an octagonal, so the name is. The ancient city covers an area of 200,000 square meters, the circumference of the city wall is 2193 meters, and the wall is up to 10 meters. East and West City has a s-shaped passage. There is a moat outside the city. The north city is surrounded by mountains and no gates. From the south gate of the west city to the east city, there is an outer wall. The city wall is built with sand, reeds, red willow and other layers, and it has been preserved so far. Due to the large walls, there is no dead angle to the city, so it is easy to guard the attack. The Octagon Barrier Building breaks through the square and rectangular pattern, and the style is strange, unlike the general ancient city. The architectural form of the city wall outside the Forbidden City in Beijing is very similar to the architecture of the Octagon City. On the city wall, the scene in the city has a panoramic view... The moat has become a small canal, there is a well at the entrance of the city, and residents come here to pull water. In the distance is Baishi Mountain... Although in 1981, the ancient city of Octagonal was listed as a key cultural relics protection unit at the provincial level, On May 25, 2006, it was announced by the State Council as the sixth batch of key cultural relics protection units nationwide. But the relics are basically in a state of no care and no protection. There are dozens of families living in the city, as well as schools, which is a complete village. The local driver master sighed and said that for many years, the city wall was not destroyed by the wind and rain, but the villagers dug it! The villagers' houses are damaged, and the city walls are dug for repairs! In a few years, the ancient city of Octagon will not be seen!