From March 21 to April 11, a team of 10 international exploration experts, alongside Vietnamese specialists, conducted a survey in Phong Nha - Ke Bang National Park in central Vietnam.
After 20 days in the field, the team discovered 26 new caves and surveyed three previously known ones, recording a combined length of 13,643 meters.
Among the most remarkable findings was Cha Ngheo, identified as a vertical sinkhole with its entrance perched atop a mountain and a waterfall cascading inside.
An explorer rappelled into the cave, where its unusual structure quickly became apparent.
"The cave is L-shaped, which is very rare. This is the first time I've seen this type of cave in Phong Nha - Ke Bang," said Howard Limbert, a British caving expert with 36 years of experience exploring caves in Vietnam.
Although it was the dry season with little rain, there was a strong stream flowing inside the cave.
The team was unable to fully explore it due to the cold conditions, which required the use of diving suits.
Limbert said the cave is unsuitable for tourism development, as the powerful water current presents significant safety risks.
In addition to Cha Ngheo, the expedition also discovered Mo Roo Cave, measuring approximately 500 meters in length and featuring its own underground stream system.
The cave's entrance is situated at a higher elevation, with a stream running below.
Below the cave, there is a stream flowing over stalactites, creating a distinctive subterranean landscape.
Around 66% of its length can only be navigated by swimming.
Despite these conditions, the expedition team assessed the cave as suitable for controlled access and potential tourism development.
A specialist crouches to enter Mo Roo Cave, having to navigate underwater to progress deeper inside.
The team spent more than a day and a half completing a full survey of the cave.
To date, experts from the British Cave Research Association and Phong Nha - Ke Bang National Park have identified seven major cave areas including three primary systems: Phong Nha, Vom, and Nuoc Mooc. In total, 472 caves have been recorded, with a combined surveyed length exceeding 254 kilometers.
The expedition team also discovered Ma Dom Cave in Kim Dien Commune, measuring 1,257 meters in length.
The cave is notable for its large scale, significant scientific value, and the presence of a flowing underground stream.
A section of Ma Dom Cave is illuminated by natural sunlight, revealing its internal formations.
Pham Hong Thai, director of Phong Nha - Ke Bang National Park, said the 2026 survey has significantly expanded the park's cave database, further affirming its outstanding geological, geomorphological, and karst system values.
"These caves not only have scientific significance but also open up many potentials in conservation, research, and sustainable tourism development, contributing to enhancing the value and status of the world natural heritage site in the future," he said.
Phong Nha - Ke Bang National Park features extensive, continuous limestone formations with minimal faulting, earning it the nickname the "kingdom of caves."
Around 40 caves have been opened to tourism, notably Son Doong, the world's largest.
An expedition exploring the caves of Phong Nha - Ke Bang.
Video by the British Vietnam Caving Expedition Team
