They are a patrol road and a ditch for defence, which were excavated on the Chongam-Dong Earthen Walls in Taesong District, Pyongyang. The walls served as ones for defending Pyongyang, the capital of Ancient Korea.

The road, found outside the walls, is paved with flat stones, and it is 1.8 meters wide and 20 meters long.

Similar roads have been discovered sometimes inside the walls, but never outside the walls in Korea so far.

This road was confirmed to be used for patrolling the walls in the period of the Koguryo Dynasty.

The ditch is 4 meters in width and 1.5 meters in depth. In view of its structure, this was for preventing aggression by outsiders.

These facts have been scientifically proved by a research team of Kim Il Sung University.