Recently, I have been to the Tongwancheng site of Yulin. When I read the "Northern Dynasty Zhi" in the early years, I was impressed with the city. I took loess and cooked it, and then poured it into the city wall. The supervision union used paper to test it. Once the paper could be inserted into the gap, the people in the city would be sentenced to death. I didn't go there, but I came to the site of Camel City. It is close to Tongwan City, the only remaining site in the sixteen-nation period. Besides multiple accidents, I don't even know that there is this place after this.