If you’re interested in Vietnam's 20 century history, go to the DMZ, advises Vietnam Travel. Visitors can still see Camp Carroll (“one of the largest bases of the US Marine Corps”), the Truong Son National Cemetery, (“the official Vietnamese war cemetery”), and the Vinh Moc Tunnels (“where an entire village tried to wait out the war”).
The DMZ was created after after Vietnam was divided into two in 1954, explains Vietnam Travel -- “North Vietnam, which was communist-run, and South Vietnam, which was a pro-western republic.” The DMZ was the strip of land between the two, “attempting to create a buffer between the two hostile states,” but it “didn't last long.” By 1956, communists in South Vietnam attempted to overthrow the government with the North's help, the US “started pouring resources -- and eventually troops -- into the area,” and the “bloody and devastating Vietnam War began.” Today the DMZ is mostly a tourist attraction -- “rusted-out artillery and tanks can still be found lurking about … fossilized reminders of an all-too recent past.”
The Vinh Moc network of tunnels “housed an entire village for years,” explains Atlas Obscura, and even had “a hall for screening movies.” The tunnel network in the DMZ was created by local villagers in 1965-66 because the US military believed the residents of Vinh Moc were supplying food and ammunition to Con Co island, a nearby North Vietnamese military base -- “to force the villagers to move out, American forces rained up to 500 rockets a day on the region.” But instead of fleeing, “the villagers went underground.”