Seoul's Hidden Underground: A Complete Guide

The interior of Seoul's underground passages after 40 years

Ah, Seoul! A city where modernity and tradition meet, offering an intoxicating mix of gleaming skyscrapers and historic palaces. But wait, there's more! Imagine a mysterious underground space, hidden right in the heart of the city. Yes, you heard me right! Seoul's hidden underground space is an attraction that arouses curiosity and excitement. So why not add a touch of adventure to your trip to South Korea by exploring this mysterious place? Hold on to your hats, as this guide takes you on a fascinating journey through Seoul's hidden underground space. Seoul.

What is Seoul's Hidden Underground Space?

The interior of Seoul's underground passages after 40 years

Seoul's hidden underground space is a mysterious area located 13 metres beneath Seoul's City Hall Square. Measuring 335 meters long, 9.5 meters wide and 4.5 meters high, this space was built 40 years ago for reasons as yet unknown. It is located just below CitiStar, an underground shopping mall that connects the City Hall subway station to Euljiro 1-ga station via Seoul Square.

Why is it so fascinating?

What makes this space so fascinating is its mystery. Nobody really knows why it was built. Some speculate that it was intended to link two metro stations in 1983. Add to this the stalactites and stalagmites formed inside, and you have a place that looks like a scene from a sci-fi movie.

How to visit Seoul's Hidden Underground Space?


Reservations and Guided Tours

The Seoul City Government is offering bookable public tours of the tunnel every Friday and Saturday until September 23. Reservations can be made on the city government's booking website ( It's important to note that space is limited to 10 people per one-hour session, so be sure to book in advance to guarantee your place.

What you need to know before leaving


Visitors will be equipped with safety helmets, masks and water. In addition, trained guides will accompany you throughout the tour to ensure your safety and answer any questions you may have. Please wear comfortable clothing and sturdy walking shoes.


You can enter the dusty tunnel through Seoul's green toy library at Euljiro 1-ga underground station. For those using public transport, the nearest subway station is Euljiro 1-ga on Seoul Metro Line 2. Orientation signs are also available to guide you to the tunnel entrance.


The tour is usually free, but it's always a good idea to check the latest information on the booking site for any updates on fees.

Age restrictions

Please note that the minimum age for taking part in the tour is 12 yearsMinors must be accompanied by an adult.

What is the future of this space?

The Seoul city government has launched a public competition to gather ideas on how best to use this underground space. The aim is to transform this space into a leisure area based on citizens' ideas.


Seoul's hidden underground space is more than just a place; it's an experience. Whether you're an adventure-seeking traveler or simply curious, this place offers a unique opportunity to discover a hidden aspect of Seoul. So, are you ready to take part in this underground adventure?

FAQ On Seoul's hidden underground

Where is Seoul's hidden underground space?

It is located 13 meters below Seoul's City Hall Square.

How can I book a guided tour?

You can book a tour on the city government's booking site

Is it safe to visit this space?

Yes, safety measures are in place, including hard hats and masks.

Why is this space so mysterious?

It was built 40 years ago for unknown reasons, adding a layer of mystery.

What does the future hold for this space?

The Seoul city government plans to transform it into a leisure space based on citizens' ideas.

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