Truong Son mountains, 7/74: North Vietnamese Army soldiers travel up a muddy hill on the Ho Chi Minh trail. By 1974 many parts of the trail had four lanes, and facilitated speedy travel; following the 1973 Paris Peace Accords, travel on the trail was also relatively safe from US bombing, though there were still landmines and the threat of South Vietnamese Army attacks. Photo: © Lam Tan Tai