In 1990, in Vietnam, a man looking for shelter accidentally discovered the world’s largest cave, which was untouched for millions of years and filled with previously unseen animals, rain forests, and its own weather.
Oxalis Adventure, a company that now offers tours of the area in Vietnam, tells the story of how the world’s largest cave, which remained unknown for millions of years, was first discovered in 1990 but not explored.
A local man named Ho Khanh said he had looked at the local job boards near me without finding work, so he searched in the jungle looking for food and timber he could use to earn a modest income. He discovered the Son Doong Cave while searching for food and timber in Phong Nha-Ke Bang National Park.
During his search, he accidentally stumbled across an opening in a limestone cliff. The first thing he noticed were clouds billowing out from the entrance. At the entrance, he heard the sounds of a river raging from somewhere inside. He was intrigued but did not explore further. Instead, he returned home and forgot about the cave.
It would remain unexplored and unknown to anyone else except Ho Khanh for another 18 years.
In 2008, Howard and Deb Limbert of the British Cave Research Association (BRCA), were conducting exploratory caving expeditions in Vietnam. They eventually heard the stories about Ho Khanh and the strange cave he discovered. After some urging, the British researchers convinced him to rediscover the location of the cave. It took several attempts to find it again.
In 2009, Ho Khanh led Howard and Deb Limbert, as well as a team of other caving professionals to the opening. After the professional researchers completed their first survey in 2009, they concluded that the cave contained the largest cross-section of any cave anywhere on Earth. They named the cave “Son Doong.”
Cave experts are researching a connection between Son Doong Cave and neighboring Thung Cave. They say if the connection is made, Son Doong will be the largest cave in the world by volume, as well as by cross-section.
Oxalis Adventure says that, the original discoverer of the cave “Ho Khanh is still an integral part of every Son Doong Expedition.”
Until the first exploration in 2009, Son Doong Cave had remained untouched for millions of years. Explorers would soon discover the cave held a wealth of secrets.
Inside was a vast area of underground rain forests and rock formations called stalagmites that were the size of tall buildings. The ceiling of the cave extended 650 feet, which is more than twice the height of the Statue of Liberty.
Living in the cave were never-before-seen animals. Howard Limbert and his team, along with scientists from Hanoi University, discovered seven new species of animals living in the cave not seen anywhere else in the world.
The original sighting that drew Ho Khanh’s attention to the cave was clouds billowing out from the opening. Explorers eventually discovered that the cave did indeed have clouds from its own weather system.
“When the heat reaches inside the cave, it evaporates the water generating ‘clouds’ inside the cave,” said Josh White, a cave safety expert and guide with Oxalis Adventure, who spoke to AccuWeather. “The airflow of the cave varies depending on the pressure and temperature outside each of the four main openings.”
“During the winter months, there are no clouds in the cave,” Howard Limbert told AccuWeather. “It is crystal clear. At this time, the cave temperature is warmer than the outside temperatures.”