The area either side of the old demarcation line that once separated North and South Vietnam was and is still known as the Demilitarized Zone, or simply the DMZ. However, considering that this region suffered under the greatest deluge of bombs in the history of warfare it was anything but demilitarized. To be precise the DMZ spanned from the Ben Hai River on the coast to the old Marine combat base of Khe Sanh, roughly the 17th parallel. The area 5km north and south of this line constituted this zone, which saw some of the heaviest fighting in the American war. Many of the historically significant sites from this era lie along highway 9. Many visitors to the region make a pilgrimage to Hien Luong Bridge on the Ben Hai River, Con Thien firebase, The Rockpile Observation Post and Khe Sanh combat Base where there is an informative museum and the remnants of the airstrip. Another interesting site in the vicinity is the Dakrong bridge which is located on a spur of the Ho Chi Minh Trail, an area populated by the Bru minority group. A journey to this part of Vietnam is a must for military history buffs.