Seun Sangga is Seoul's first mixed-use complex.

Constructed between 1967 and 1972, the elaborate structure sits atop a strip of land measuring 50 m x 1.2 km, which had been flatted during the Second World War as a way to contain the spread of fire in the event of an air raid and to act as an evacuation corridor.

It's a modernist development that is very much of this period. It's massive, complicated in section and, in many ways, completely disconnected from its surrounding urban context. Flanking the various buildings are elevated and covered walkways.

So it is perhaps not surprising that this development has followed a similar fate to many others of this era. While it was initially viewed as being quite modern and desirable -- it was one of the first buildings in Seoul to have elevators -- Seun Sangga was quick to start showing signs of decline.

In fact, by as early as the 1970s, the complex became known for its porn shops and a bunch of other informal economy-type activities.

It's an interesting, though familiar, story.

If you'd like to learn more, I recommend you check out this episode of the Urbanist and this article from The Architectural Review. The photos in the article are good accompaniment to the audio-only Urbanist episode, so make sure you flip through them.