If you look in the right place, beneath the bustling streets in the heart of Seoul, you will come across something unexpected: stalactites.
They hang ominously from the dank ceiling, a witness to the passage of time and decades of neglect.
These mineral deposits have gathered under Seoul Plaza, probably one of South Korea’s most well-known spaces, famous for hosting everything from protests to concerts, in a vast mysterious underground tunnel the purpose of which even city officials are unsure of.
The tunnel – which stretches on for 335 metres and covers an impressive 3,000 square metres – has remained hidden for decades, until now. Public tours of this urban oddity are being offered for the first time and for a limited time.
The starting point for the guided tour is suitably James Bond. After pulling on a dust mask, safety helmet, and protective shoe covers, we enter through the backdoor of a now-demolished toy library in an underground arcade, stepping into complete darkness.
Every few minutes, you can hear the rumble of subway Line 2 below .
The tunnel is located just 13 metres below Seoul Plaza, beneath the city’s first underground shopping mall between Euljiro 1-ga and City Hall stations.
One tour participant, Lee, describes the experience as “a little scary”, mentioning that he had passed by the toy library many times before without realising it held a secret. “I hope that whatever this site becomes, visitors will be able to experience the city’s history,” he says.
It is easy to assume the space served as an air-raid bunker, which is not uncommon in South Korea given the country’s proximity to North Korea. But its original purpose is unknown. City officials think it might have been built to connect two subway stations but never used.
The one-hour tour provides insights into the city’s planning history, including the construction of the Seoul subway system starting in the early 1970s.
Our guide explains that the construction of Line 2 involved excavating downward from the surface, rather than using the more modern tunnel boring methods of today. When Euljiro 1-ga station opened in 1983, this unused space was presumably created, covered up, and left untouched for over 40 years.
The unveiling of this hidden space forms part of a city project aimed at turning subway stations into urban attractions. Citizens will now have until mid-October to submit suggestions for how to utilise it.
Hong Sun-ki, head of Seoul’s Future Urban Spaces Planning Bureau, describes the tour as “an opportunity to learn about the city’s hidden stories” and explore a space “that you could have never imagined”.
It also begged the question: what other hidden secrets might the city hold?