DMZ
The Military Demarcation Line (MDL) is surrounded by the Demilitarized Zone (DMZ) under the provisions of the Armistice (cease-fire) Agreement signed on July, 1953. The Military Demarcation Line runs 155miles and separates the South and the North. Southern and Northern boundaries of the DMZ are located 2km apart from the MDL.

The Demilitarized Zone, which consists of the area between Southern and Northern boundaries of the DMZ, was established to serve as a buffer zone to prevent any means of provocative action and collision between the South and the North.

3rd infiltration tunnel is only 44 kilometers or less than an hour's drive from Seoul, the third tunnel was discovered in October 1978. Almost identical in structure to Tunnel Ⅱ, the 1.635 kilometer-long tunnel, 1.95 meters high and 2.1 meters wide, penetrates 435 meters south of the Military Demarcation Line at a point only 4 kilometers south of the Truce Village of Panmunjom. It runs through bedrock at a depth of about 73 meters below ground. Capable of moving a full division per hour, plus their weapons, it is evidently designed for a surprise attack on Seoul.