Vietnam is famous for many things—its military victories over France and the United States, its beautiful green landscape, its noodle soups—but did you know that it also has the world’s largest cave? That cavern, located in Phong Nha-Ke Bang National Park in central Vietnam, made history in 2009 when it was measured at 75 miles long. (It was featured on the cover of National Geographic magazine in January 2011.) It’s still accessible only to explorers, but the park contains roughly 300 other caves and grottoes, which are part of the oldest, and one of the biggest, limestone (or karst) regions on the planet.
The prospect of seeing that landscape was too tantalizing to pass up. So we took the train to the nearest big town, coastal Dong Hoi, and hired a car to visit the park for a day. First we stopped for a walk on the Nuoc Mooc trail, which winds through lush forest and along a river on a boardwalk of bamboo poles. It’s an inviting place for a swim and is popular during the summer months. The day we visited, though, we had it almost all to ourselves (some skinny-dipping may or may not have occurred).
Next we visited the second largest cave in Vietnam, called Phong Nha, which can only be reached by boat. After motoring up the river for 5 kilometers to the mouth of the cave, our driver cut the engine and paddled us for another kilometer through the cavern. We glided in awe through the dimly lit, massive space, past enormous stalactites, pillars, and rippling formations created from millennia of water seeping through the porous rock and leaching out colorful minerals. At one point the boat pulled up to a sandy bank, where we could get out and walk to get a closer view of all of the amazing shapes. The occasional drop of water from above reminded us that the process is still going on.