Korea's DMZ and JSA at Panmunjom

Infiltration Tunnel #1 Date of Discovery: November 15, 1974 Location: 8km northeast of Korangpo Dimension in meters: 3,500x1.2x0.9 Length of tunnel(south of MDL): 1,000 meters Depth from ground: .45 meters Structure: concrete Capability of moving troops an hour: 1 regiment Distance from Seoul: 65km	The first tunnel was discovered in November 1974 in the Western Sector of the DMZ near Gorang-po. With an estimated total length of 3.5 kilometers, it extends one kilometer south of the Military Demarcation Line that divides the DMZ. The walls and ceiling of the tunnel, 1.2 meters high and 0.9 meters wide, are reinforced with concrete slabs. It has the capacity to move an entire regiment per hour through it. The tunnel was lit with lamps connected to 220-volt power lines. Equipped with a narrow-gauge railway, rail cars and drainage devices were also found inside. This tunnel is located only 65 kilometers north of Seoul.
Infiltration Tunnel #2 Date of Discover: March 19, 1975 Location: 13km north of Chorwon Dimensions in meters: 3,500x2x2 Length of tunnel (south of MDL): 1,100 meters Depth from ground: 50-160 meters Structure: Arch-shaped & bored through bedrock Capability of moving troops an hour: 30,000 troops & field artillery Distance from Seoul: 101km	Twice as wide as the first tunnel, the second tunnel was discovered in March 1975 in the Central Sector of the DMZ, about 13 kilometers north of Cheorwon. Measuring two meters high and 2.1-2.2 meters wide, the arch-shaped tunnel is large enough to move heavy weapons as tanks, field artillery, and armored personnel carriers. More than 30,000 troops could move, three to four abreast (a division in strength), per hour. Bored through 3.5 kilometers of bedrock at a depth of 50-160 meters below ground, the 2nd tunnel extends 1.1 kilometers south of the Military Demarcation Line to a point 101 kilometers from Seoul. A spacious troop assembly area was carved out inside the tunnel, which has three exits.
Infiltration Tunnel #3 Date of Discover: October 17, 1978 Location: 4km south of Panmunjeom Dimensions in meters: 1,635x1.95x2.1 Length of tunnel (south of MDL): 435 meters Depth from ground: 73 meters Structure: Arch-shaped & bored thru bedrock Capability of moving troops an hour: 30,000 troops & field artillery Distance from Seoul: 44km	Only 44 kilometers from Seoul (less than an hour's drive), the third tunnel was discovered in October 1978. Almost identical in structure to Tunnel 2, the 1.635 kilometer-long tunnel is 1.95 meters high and 2.1 meters wide.
It penetrates 435 meters south of the Military Demarcation Line at a point 4 kilometers south of Panmunjeom, running through bedrock at a depth of about 73 meters below ground. Capable of moving a full division (plus their weapons) per hour, it was evidently designed for a surprise attack on Seoul. This tunnel is only 2 kilometers from a key outpost defending the Munsan corridor leading to Seoul. The third tunnel burrowed by the North was discovered near the armistice village of Panmunjeom only 44 kilometers north of Seoul. The third tunnel was also capable of moving a full division per hour, plus their weapons, with the intention of clandestinely infiltrating them into the rear areas of the South to form a second front.
Infiltration Tunnel #4 Date of Discovery: March 3, 1990 Location: 26km northeast of Yanggu Dimensions in meters: 2,052x2x2 Length of tunnel (south of MDL): 1,052 meters Depth from ground: 145 meters Structure: Arch-shaped & bored thru bedrock Capability of moving troops an hour: massive forces & field artillery Distance from Seoul: 203km	The fourth tunnel, which is located along one of the most strategic routes in the Eastern Sector, was discovered in March 1990 only 26 kilometers northeast of Yanggu. This tunnel is buried at a depth of 145 meters below ground and measures two meters high and two meters wide. Almost identical with Tunnel 2 and Tunnel 3 in size and structure, the fourth tunnel intrudes 1.03 kilometers south of the Military Demarcation Line and is designed to infiltrate massive forces into the Sohwa-Wontong corridor, the major access route to the Yeongdong (Seoul- Gangneung) Expressway. The fourth tunnel, the first found in the Eastern Sector, was discovered about 26 kilometers northeast of Yanggu. With this discovery, we know that North Korea has dug invasion tunnels along the entire stretch of the front line.