Apparently, There Are Tunnels That Run Between North And South Korea
In November of 1974, a tunnel was purportedly found that could lead over 30,000 soldiers from North Korea into South Korea. It was 3.5 kilometers long, and it was only 65 kilometers from Seoul. Another one was found in March of 1975 and was 1.1 kilometers long. A third tunnel was found in October of 1978, at 1.6 kilometers in length this time and 73 meters underground. Then a fourth tunnel was found in March of 1990. Although one retired South Korean general claims that there are over 84 tunnels all near the border of North and South Korea, no one knows the exact number for sure. The ones that have been found are safeguarded round the clock by South Korean forces.
