Masonry of the Gwangtonggyo Bridge on the Cheonggyecheon Stream.
If these don’t look like the kind of stones you’d ordinarily use to build a bridge, it’s because they aren’t. The stones were originally used to form the protective granite wall around the burial mound of Jeongneung, the tomb of Queen Sindeok, the second wife of Joseon Dynasty founder Yi Seong-gye. Yi’s energetic but ruthless son (by his first wife) Yi Bang-won - later King Taejong - had a particular hate-on for her since she tried to put her own sons on the throne instead of him. After he became king, Yi Bang-won ordered her tomb moved outside of the city walls (to its current location in Seongbuk-gu) and some of its stonework used to repair the Gwangtonggyo Bridge, which had collapsed in a flood in 1410. In so doing, Yi made it so that the residents of the royal capital would regularly trod upon the tomb of his hated stepmother.