Acting on information provided by local residents, Quang Tri-based adventure tour operator Jungle Boss Co. Ltd. and the management board of Phong Nha-Ke Bang National Park recently completed a six-day survey of the cave.

Le Luu Dung, director of Jungle Boss, said on Thursday that the discovery had astonished the local caving community because of the cave's extraordinary geological features.

The cave has been named Thang Cave, or Victory Cave in English, after the local resident who first identified its location.

It lies along the route between Voi (Elephant) Cave and Ma Da Lake in the Ma Da Valley, within the park's strictly protected zone.

Surveyors found that Thang Cave stretches approximately 3,000 meters and averages 70 meters in width, with some sections measuring more than 100 meters across.

The cave has two entrances and branches into two separate passages.

The entrance measures about five square meters, while the exit is so narrow that only one adult can squeeze through at a time.

To reach the cave floor, the expedition team had to rappel about 20 meters.

At the bottom, they encountered what they described as a spectacular 'stalactite palace' formed over hundreds of thousands of years.

Nearly the entire length of the cave is lined with diverse stalactite formations, creating what explorers described as an unprecedented 'stalactite palace.'

Some stalagmite columns rise as high as 50 meters, while stone curtains hang from the ceiling along the walls.

Massive stalagmites stand like towering fortresses, and a remarkable variety of rock formations and stalactite features fills the cave, leaving even experienced explorers in awe.

One of the expedition's most remarkable discoveries was a large number of unusually large 'cave pearls,' which veteran caving experts said they had never encountered before.

The smooth, white, spherical 'cave pearls' were found clustered inside natural rock cavities, with some cavities containing numerous pearls of varying sizes.

Following the survey, Jungle Boss submitted a proposal to the park management board to add Thang Cave to the existing two-day, one-night Ha Ma Da Valley-Tra Ang Cave ecotourism route.

The proposal was approved by the park management board.

Phong Nha-Ke Bang National Park was first inscribed as a UNESCO World Natural Heritage Site in 2003 for its outstanding geological and geomorphological values.

The designation was expanded in 2015 to also recognize its exceptional ecosystems and biodiversity, and it was added to UNESCO's World Network of Biosphere Reserves in June 2026.

In addition, the site forms part of a transboundary World Natural Heritage property shared with Hin Nam No National Park in Laos, which UNESCO recognized in July 2025 as Southeast Asia's first transboundary World Natural Heritage Site.