In 2008 the city of Seoul decided to act on stories told by local residents that the Japanese military had a tunnel dug under Gungsan, near Yancheon Hyanggyo Station (Line 9), during World War II. The tunnel was discovered and plans were made to turn it into a tourist attraction with its alcoves being used as various exhibition spaces. In 2010, however large rocks fell from the roof as construction proceeded and after examination it was decided not to proceed with this plan for safety reasons, and the project stalled for years. A smaller plan was enacted in which its entrance would be turned into an exhibition space, that allowed for a glimpse of the tunnel, and in May 2018 it opened to the public.
The Gungsan tunnel was dug by Koreans mobilized in patriotic service corps in the 1940s during the Pacific War. It was 3 meters underground, 70 meters long, and 2 meters in diameter. It was used to store weapons, ammunition and other war materials, and could also be used as an air raid shelter. The main military outpost in the area was Gimpo Airbase. A small hill near the tunnel known as Seonyubong was demolished to provide stone for the construction of Gimpo Airbase in the late 1930s.
I visited the exhibition hall last weekend and took the above photos. It’s open from 10-4 every day except Monday, and though the display material is in Korean the volunteer when I was there spoke English well. Seeing as you can't actually go into the tunnel, it might not be worth a visit for the tunnel alone, but it’s right behind the Gyeomjae Jeong Seon Museum, an art museum dedicated to Jeong Seon, who was served as the magistrate of the Yangcheon Prefecture in the 1740s (but who may be more familiar for the image on the back of the 1000 won bill). Yangcheon Hyanggyo, Seoul's only remaining Confucian school and shrine, is also just around the corner, but is closed until May for construction. The newly-opened Seoul Botanical Garden is also nearby in Magok-dong, and is free until May.
I’ll be leading a tour for the Royal Asiatic Society to the Gungsan area and Gaehwasan (near Gimpo Airport) taking in both museums, Yangcheon Confucian Shrine, temples, tombs, Korean War memorials, and spring flowers next Saturday, April 13. For more information about the tour, see here.