A Donga Ilbo editorial about the demolition offers more information about late 1960s development plans as well as this: "The city government of Seoul has decided to open Ahyeon Overpass to the public from 11 am to 4 pm on Feb. 8 before demolition."
The Joongang Ilbo reports on the demolition of the Ahyeon Overpass, Korea's first overpass, which was built in 1968, so that it can be replaced with a bus lane.
The old overpass symbolized Korea’s rapid modernization, triggered by a huge increase in transportation infrastructure from the 1960s to 1980s. A total of 101 overpasses were built in Seoul during that period.Just in case you had no plans for Saturday...
But these days, many of the roadways built during that time have worn down and are widely considered to be blights on the urban landscape. Since the early 2000s, urban planners have adopted a more sustainable and passenger-friendly approach, taking aesthetics into consideration.
In 2002 alone, 15 overpasses were taken down.[...]
Seoul’s decision to transform Seobu Highway, a main arterial road, into an underground road partly reflects a shift from the past.
The Seoul city government is now considering demolishing other dilapidated overpasses, including the one near Seoul Station. It has already decided to close the Seodaemun Overpass in Seodaemun District.
Acknowledging the overpass’s historical significance, the city government will allow citizens to come and walk along the overpass on Saturday before it is completely demolished.
Not all overpasses were so unsightly, however. Here is what Samgakji Rotary used to look like between 1968 and 1994:
As this blog post (the source of the above photo) notes, the rotary was also connected with trot singer Bae Ho's 1966 song 'Doraganeun Samgakji (돌아가는 삼각지),' which can be heard here, and which is also referenced in some of the older restaurants in the area.