“When we first got to the collapsed doline, that skylight up there, I was with another caver and we both had four-year-old sons, so we were experts on dinosaurs, and the whole scene reminded us of something right out of Sir Arthur Conan Doyle’s novel The Lost World,” he says. “When my partner went exploring forward into the sunlight, I told him to ‘watch out for dinosaurs,’ and the name stuck.”
Two decades ago, the leaders of this expedition, Howard Limbert and his wife, Deb, became the first cavers to visit Vietnam since the 1970s. Back then, the country’s caves were legendary but unexplored. In 1941 Ho Chi Minh had planned his revolution against the Japanese and French in Pac Bo Cave north of Hanoi, and during the Vietnam War thousands of Vietnamese hid from American bombing raids inside caves. The Limberts, experienced cavers from the Yorkshire dales of northern England, made contact with the University of Science in Hanoi and, after obtaining sheaves of permits, mounted an expedition in 1990. They’ve made 13 trips since, not only discovering one of the longest river caves in the world—12-mile Hang Khe Ry, not far from Son Doong—but also helping the Vietnamese create 330-square-mile Phong Nha-Ke Bang National Park, which now attracts a quarter million Vietnamese and foreign visitors a year. Tourists, who dramatically increase the income of local villagers, come to see the park’s namesake show cave, Hang Phong Nha, which workers light up like a psychedelic rock concert.