We were driving along the highway when we saw a square brick structure standing tall on the mountain from a distance. However, none of us knew what it was. Upon approaching and seeing a stone stele nearby, we learned that it was a watchtower, also known as a beacon tower, of the Liaodong Great Wall. This section of the Great Wall has already been destroyed or remains only as ruins, which is quite different from the Great Wall I have seen in other places.