Ben Hai River
Twenty - two kilometers north of Dong Ha, Highway 1 crosses the Ben Hai River - once the demarcation line between North and South Vietnam - over the decrepit Hien Luong Bridge. Until 1967 (when it was bombed by the Americans), the northern half of the bridge that stood on this site was painted red while the southern half was yellow. Following the signing of the Paris cease - fire agreements in 1973, the present bridge and the two flag towers were built. A typhoon knocked over the flag pole on the northern bank of the river in 1985.