Introduction to the ancient city wall: When you climb to the top of the mountain, you can see several sections of the city wall made of huge stones. It is said that this was the defensive city wall built by King Ji to resist foreign enemies. These stones are all cut from huge rocks. Small ones weigh hundreds of kilograms and large ones weigh five or six tons. People are not only curious about how the ancients thousands of years ago transported them to this steep cliff and then built it. This ancient city wall has survived for thousands of years.