Taesong Fortress

The Taesong Fortress was a city fortress and the capital of Koguryo, until 668. It lies between the rivers Taedong and Pothong. Parts of the city walls, its gates and pavilions still remain in the city of Pyongyang, North Korea. The fortress has been dated to the 3rd-5th centuries, during the Koguryo period.
The walls of the fortress have a circumference of 7,218m. Built at the foot of Mount Taesong, the fortress provided protection for the capital, and held wells, storehouses and armories behind its walls. It remains one of the largest stone fortifications found in Korea in both its circumference and the area enclosed.
It is national treasure No. 8 of the DPRK.