Jamsil (蠶室, "Silk Room") used to be a floodplain where silkworms were raised. In the 1960s, to cope with Seoul's population growth, the floodplain was filled, and the government developer, Korea Housing Authority, started building apartments there.

Unlike Phases 1-4 which were coal-fired 5-story buildings with no elevator (and lucky to have indoor plumbing), Phase 5, built in the mid-1970s and standing 15 stories tall, was state-of-the-art for its time, with elevators, heating via hot water piped in from a central boiler plant, and for those few lucky enough to own a private car, ample parking (woefully inadequate today, of course).

Jamsil really boomed, as it was annexed into Seoul in 1973, subway service and Olympic facilities were added in 1980, and Lotte World opened in 1989 right after the Olympic Games. Today, Phase 5 looks very dated - Phase 1-4 were so obsolete they were demolished and replaced with state-of-the-art 30-story luxury highrises (free right to move in for displaced former residents per Korean law).

I am just across from the complex, on the other side of National Highway 3. This also happens to be, as indicated on the road signs, the southern anchorage for Jamsil Bridge, which crosses the Han River to carry National Highway 3 further north, toward Achasan Fortress (and beyond to Uijeongbu, Dongducheon, and Wonsan in North Korea).