Hidden SideThe Hidden Side of ArchitectureNo.080Published October 8, 2026

Okcheon's 4 kilometers were the last of the Gyeongbu Expressway to connect because the hardest stretch needed a Geum River bridge and the Dangjae Tunnel, and its paving joined only at midnight, June 27, 1970

In the National Archives of Korea's record of the Gyeongbu Expressway, the last of its 428 kilometers from Seoul to Busan to connect was 4 kilometers in Okcheon. This stretch of the Daejeon section was the hardest, where a bridge across the Geum River and a tunnel through Dangjae, on the flank of the Sobaek Mountains, had to be built together; after a rockfall in the Dangjae Tunnel on May 1, 1970, the tunnel paving laid in from both ends joined at midnight on June 27, and the whole route became one. That was ten days before the July 7 opening. Of the 77 people who died during construction, 9 died during work on the Dangjae Tunnel. We attached the institutional source to each sentence of the video.

✔Checked against the institution's original text △Original not available, checked through news reports ○Our interpretation or a linking sentence Tap a mark to open its sources. Tap a sentence to play the video from there. The video is narrated in English.

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Sources

Every source behind the script, including claims we checked and left out.

How we checked

Checked on October 8, 2026. We compared the video against the originals of the National Archives of Korea records content "The Gyeongbu Expressway" (국토의 대동맥 경부고속도로; an overview, chronology and statistics compiled from records held by the National Archives of Korea and the Construction Record of the Seoul–Busan Expressway (서울-부산간 고속도로 건설지, 1974), among others): five pages of "Laying a Road Across the Land" (sections, Seoul section, Daejeon section, Daejeon–Daegu, Daegu–Busan), the "Expressway Chronology" (1968–1969 and 1970), and the "Statistics" page. Every sentence of the video was confirmed in institutional originals, so there are no sentences confirmed only through news reports (△).
  • Besides the rockfall of May 1, 1970, the chronology lists a separate rockfall on September 9, 1969, and an explosion on September 17, 1969, at the Dangjae Tunnel. The video mentions only the one on May 1, 1970, in the year of the opening. The chronology does not give the extent of damage for each accident, so the video does not either.
  • Claims such as "there were 13 rockfalls" or "fast-setting high-early-strength cement was used" appear in news reports and other videos, but we could not find them in institutional originals, so they are not in the video.
  • "This stretch was delayed because of the rockfall" is not in the original. The reason for the delay given in the original is that it was the "hardest stretch," where the Geum River bridge and the Dangjae tunnel had to be built together, and the video stays within that.
  • The start date of the Daejeon–Daegu section differs within the same site: "groundbreaking ceremony on January 4, 1969" in the main text and "January 14, 1969" in the chronology and section table. The video gives no date and says only "only the next year."
  • The National Archives of Korea gives the number of workers who died during the Dangjae Tunnel work as 9. Some news reports and other channels give 11. The overall 77 is the number of names engraved on the memorial tower, and there are news reports that the counting method is disputed.
  • We could not find an institutional original on the Dangjae Tunnel today (the old route, its current use), so the video does not mention it.

Corrections

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