Tucked away among the karst mountains of the Annamite Mountain Range near the Vietnamese border, this isolated valley initially served as the shelter and hiding place for Pathet Lao leaders, including Kaysone Phomvihane and Prince Souphhanu Vong, during the Vietnam War (1954–75). The caves in the valley were used not just as their homes, but as communication centers, hospitals, and small factories. Also used as a secret military area, it was the location of prison camps where key members of the former regime, notably the royal family, were incarcerated. These caves are now open to visitors. It is also possible to visit another huge cave nearby where mass political rallies and musical and theatrical performances from friendly Socialist countries were held.
The caves are best visited as a day trip from Sam Neua on the obliga- tory guided tour, which includes excellent oral histories delivered via audio headsets. Visitors with enough time, how- ever, can stay overnight in any one of the local guest- houses and explore the quiet back roads of this spectacular and pristine valley on rented bicycles.