It was built between the 3rd and 5th century by linking six peaks of Mt. Taesong.
As one of the largest forts in the period of Koguryo Dynasty, it is over 9 km long. It played an important role in the battle to beat back the enemy invasion for a long period of time.
The existing 200-m-long section of the walls on Somun Peak was restored to the original state.
