PHOTOS: Secret Cold War-era bunker now art space in Seoul

The bunker, discovered in 2005 during the construction of a transit center, was supposedly built in the 1970s on orders from the then-head of South Korea's presidential security following the assassination of late President Park Chung-hee's wife. With no original plans or documents, the bunker's purpose remained a mystery until investigators pieced together its Cold War origins.

In 2013, Seoul officials designated the site as a "future heritage site." Four years later, the Seoul Museum of Art opened the space as SeMA Underground Bunker, hosting exhibitions in the former bomb shelter.