1 of 4 known infiltration tunnels under the North & South Korea border, with regular guided tours.
The tunnel is now a tourist site, though still well guarded.
Visitors enter either by walking down a long steep incline that starts in a lobby with a gift shop or via a rubber-tyred train that contains a driver at the front or the back (depending on the direction as there is only one set of rails) and padded seats facing forward and backwards in rows for up to three passengers each. Photography is forbidden within the tunnel. The South Koreans have blocked the actual Military Demarcation Line in the tunnel with three concrete barricades. Tourists can walk as far as the third barricade, and the second barricade is visible through a small window in the third.
South Korea, Gyeonggi-do, Paju-si, Gunnae-myeon, 점원리 산172