When American bombing raids north of the DMZ intensified in 1966 the inhabitants of Vinh Linh District began digging down into the red laterite soils, excavating more than fifty tunnels over the next two years. Although they were also used by North Vietnamese soldiers, the tunnels were primarily built to shelter a largely civilian population who worked the supply route from the Con Co Islands lying 28km offshore. Five tunnels belonged to Vinh Moc, a village located right on the coast where for two years 250 people dug more than 2km of tunnel, which housed all six hundred villagers over varying periods from early 1967 until 1969, when half decamped north to the relative safety of Nghe An Province. The tunnels were constructed on three levels at 10, 15 and 20–23m deep (though nowadays you can’t visit the lowest level) with good ventilation, freshwater wells and, eventually, a generator and lights. The underground village was also equipped with a school, clinics and a maternity room where seventeen children were born. Each family was allocated a tiny cavern, the four-person space being barely larger than a single bed. They were only able to emerge at night and lack of fresh air and sunlight was a major problem, especially for young children who would sit in the tunnel mouths whenever possible. In 1972, the villagers of Vinh Moc were finally able to abandon their underground existence and rebuild their homes, rejoined by relatives from Nghe An a year later.