Karst hills rose spectacularly around us as our boat put-putted upriver. We passed grazing buffalo, playful, naked children, a church spire shrouded by dense foliage, and boxy pastel houses lining the river.
Several tourist boats raced by, their hulls patterned with flaming serpents and covered with bright blue shelters. As far as I could see, all passengers were Vietnamese.
Up ahead was a marbled cliff-face, the cave accessible only by a foreboding slit in the rock several metres high. Our captain killed the engine and we drift towards the cavern in silence.
We were in Phong Nha Khe Bang National Park, home to Asia’s oldest karst area. The karst formation here has evolved over 400 million years and hidden from view is a 104 km network of caves and underground rivers.
I had joined a tour from Hue, and was discharged from the bus beside Son River, along with four exuberant boys from Nha Trang.
Along with a tour guide, a bored-looking professional photographer, and a husband-wife team to pilot the boat, we headed along Son River to Phong Nha Cave.
Suspense hung over us – along with the rocky lip – as we entered the thin slot that provided us access to the 44.5 km long cave. It was such a narrow opening the cave seemed impenetrable. Indeed, sometimes it was.
‘Yesterday,’ our guide said. ‘The water was too high – you couldn’t go inside.’
The pilot’s surprisingly tough pyjama’d wife ran to the bow of the boat and began to steer us through the crack with an enormous paddle. As the cave closed in on us, she replaced the paddle and guided the boat by pushing at the cavern’s drooping ceiling with her hands.
It was quiet and dark as we passed under the overhang.
Then we were through. The cave opened out to a large hall. Numerous deserted tourist boats were parked alongside the cave wall. A heavy sonorous thrum scared me, but it was just the pilot retracting the boat’s roof to give us a better view.
The Vietnamese boys moved to the bow of the boat, sat perilously close to the sides, and began to remove from their bags a certifiable picnic. They motioned for me to join them and plied me with strawberry cream-filled cakes, guava, bananas and apples – not my first or last experience of local hospitality in Vietnam. They invited the photographer to take pictures and dragged me into the camera’s sights.
The tour guide hammered away in Vietnamese and afterwards turned to me with translated one-liners as an afterthought: ‘Water comes through cracks in the ceiling’. Genius. Stalactites mushroomed from above, looking like the musical pipes of a distorted organ.
Sadly tourists are offered only the slightest of glimpses of the natural tunnel; after just over a kilometre, our boat was turned around.
We disembarked from the boat at the lip of the cave and explored stalagmites and stalactites dripping like used wax candles. The fluorescent glow of electric spotlights lent the cave a Gothic surrealism.
When we emerged once more into the playful colours of daylight, we were momentarily stunned. As we waited for our bus, the Vietnamese boys gifted me two of their professional photos. In the image, I looked overwhelmed but happy.
‘A memory!’ the boys cried and I didn’t know how to respond but to thank them for their generosity. We dispersed on the bus and did not speak to each other again. But for a few hours that day, those crazy Vietnamese boys were the best friends a solo traveller could have.