In the earliest days of the Vietnam War, North Vietnam supplied the VC in the South by two methods. The first was to extend the Ho Chi Minh Trail southward into the tri-border region of Laos/Cambodia/South Vietnam. The Trail, a labyrinth of paths, roads, river transportation systems and way-stations, was constantly being expanded and improved. It served as a logistical jugular vein, for both men and material, for the North Vietnamese war effort against South Vietnam. The second method was to transport supplies by sea. Estimates of this seaborne traffic ran as high as 70 percent. It was carried out due to the higher volume of material that could be transported by sea, as opposed to the overland route.