Hanoi (VNA) – The world’s biggest cave,Son Doong, in the jungle-filled Quang Binh province of central Vietnam, appearsto be even bigger than previously thought, according to the US Cable NewsNetwork (CNN) Travel.
Last month, a trio of British divers ventured tothe world natural heritage site of Phong Nha-Ke Bang National Park in QuangBinh to explore the cave’s waterways.
During the groundbreaking dive, they discovereda new underwater tunnel that connects Son Doong (meaning “Mountain River Cave”)with another enormous cave called Hang Thung.
Son Doong currently measures a total of 38.5million cu.m. When it’s officially connected with Thung Cave, it will add anadditional 1.6 million cu.m in volume.
“It would be like someone found a lump on top ofMount Everest, making it another 1,000 m higher,” according to Howard Limbert,technical advisor of the Quang Binh-based Oxalis adventure tour company.
He told CNN Travel that any cave in the worldwill be able to fit comfortably inside Son Doong when it’s connected.
“It’s justoutrageous in size,” he said.
Oxalis, the only company licensed to bring travellersinto Son Doong Cave, invited the British divers who aided in the rescue of thetrapped football team in Thailand in 2018 to visit the cave following therescue expedition.
“The divers did an amazing job rescuing thechildren in Thailand. We invited them on a trip to Son Doong to thank them fortheir great effort,” Limbert said.
“They wanted to do something interesting duringthe trip, so we came up with this idea of diving Son Doong, which had neverbeen done before.”
Limbert said the Oxalis team already knew thatthe water from Son Doong joined Thung Cave, through dye-testing, but no humanhas ever gone into these subterranean rivers.
“When the divers reached 78 m, they plumbed thedepths below using a line and a lead weight. Hence, they believe the offshootreaches a depth of 120 m and continues for about 1 km,” he explained.
The team wasn’t expecting the tunnels to be sodeep, because the other caves in the area are quite shallow.
“Now that we know how deep it is, we’ll bringthe special gases with us next time to enable long, deep dives,” Limbert toldCNN Travel.
The divers plan to return again in April nextyear, which is the best time of year to dive, as water levels are relativelylow and visibility is better than usual.
“I think it’s incredible that something asimportant as the world’s largest cave is still being explored and betterunderstood,” said Limbert.
“No one had ever set foot inside Son Doong until2009 and this latest discovery shows there are still an awful lot of things touncover on this planet. It’s really exciting,” he added.
One of the world’s most precious naturalwonders, Son Doong was inadvertently discovered by Vietnamese resident Ho Khanhin 1990.
“While hunting in the jungle, Khanh came acrossthe opening. He felt a blast of wind and heard the rush of a river inside... Butafter he left, he couldn’t find it again because it’s surrounded by foliage,”said Limbert, who was part of the British Cave Research Association (BCRA) teamthat first set foot inside Son Doong.
“Khanh spent many, many years trying torediscover the mouth of this cave and, finally, in 2009, he led us there. Werealised right away that it was major.”
After the BCRA explored and measured the cave,they proclaimed it the largest in the world in 2010 – so big that a New YorkCity block with 40-storey skyscrapers could be fit inside it, according toOxalis’s estimations.
Within the immense limestone cavern, there arevarious microclimates and diverse scenery, including two jungles where sunlightstreams in.
“So far we’ve only explored about 30 percent of PhongNha-Ke Bang National Park, so there’s a lot more to be discovered,” saidLimbert. –VNA