The Hien Luong Bridge - a bridge across the Ben Hai river, which was part of the border between North and South Vietnam from 1954 until the reunification in 1976. Today, the bridge is still there and seen as an important national monument to the reunification of Vietnam. Near the bridge is also a museum, propaganda war remnants and two memorials.
The old narrow bridge itself is a simple steel structure built by the French. The bridge is now just a pedestrian bridge. A modern bridge, which is next, takes all the traffic across the river on its behalf. You can walk across the old bridge over the entire length (165 meters).
The old bridge was during the war with the Americans, part of the DMZ. The acronym DMZ stands for Demilitarized zone (literally a demilitarized area). It is a buffer zone between two countries where tensions exist. In this case, it was the North and South Vietnam. https://www.vietnamsite.nl/hienluongeng.htm