The amazing finding of an underwater tunnel linking Hang Son Doong (Mountain River Cave) in Vietnam, the largest cave in the world, has caused it to unexpectedly enlarge significantly. 

Tapping into a little history ~

Led by Howard Limbert, the head of the caving team that mapped Son Doong for the first time in 2009, a trio of British divers discovered it in April while exploring the cave in Phong Nha Ke Bang National Park in central Vietnam. In 2018, a group of three divers, including Jason Mallinson, Rick Stanton, and Chris Jewell, participated in the operation to save the Thai soccer team. As part of their mission to explore Son Doong's vast network of streams, they came into a previously undiscovered tunnel that connected it to Hang Thung, another enormous cave. 
 

What is Hang Son Doong's size? 

 (Source: Google Images) 

Son Doong was already enormous, measuring more than 200 meters high (up to 503 meters in some places), 175 meters wide, and 9.4 kilometers long. It was large enough to contain many forty-story skyscrapers standing straight and easily accommodate any of the other largest caves in the world. According to Limbert, who spoke with CNN recently, the latest discovery increases the volume of the planet's already 38.5 million cubic meters by 1.6 million cu meters. This is the same as climbing Mount Everest, which is 8848 meters high, and finding a mound that makes it 1000 meters higher. Ho Khanh, a local, made the initial discovery of Son Doong in 1990. He discovered a deep hole at the foot of the rock that was producing wind and even puffs of cloud while seeking refuge from a storm at the base of a massive cliff in the middle of the jungle. He didn't go any farther, and when he did, Limbert and his group of divers found the entry again, and it was forgotten for 19 years.

There is nowhere like this place anywhere in the world ~ 

 (Source: Google Images) 

Other life species abound in the cave. Numerous monkeys may descend 200 meters to explore the cave's rainforest, where they gather snails. There are places where you can find snakes and other creatures including rats, squirrels, flying foxes, and bats. Seven other species of fish, spiders, scorpions, shrimp, woodlice, and plankton have been found over time; they are all entirely white and have no eyes, which is the evolutionary result of living in total darkness. However, there is still a lot to see in the cave, especially since two sinkholes light up certain areas of it with breathtaking sunshine. Sinkholes can be open, covered, buried, or partially filled with debris, and can vary in size from shallow holes to pits that are more than 50 meters deep. They are often funnel-shaped, with the wide end open at the surface and the narrow end at the bottom. The largest stalagmites in the world and a jungle with trees as tall as 50 meters can be found below the surface. It's not only about the size, though that does matter (according to the sources)—it's also about the variety of weird and incredible spots inside the cave!

Planning To Visit ? 

Although there is stringent control over entry, just 1000 people are allowed into the cave annually. Howard Limbert and his wife Deb are technical directors for Oxalis Adventure Tours, which is the only company that plans and conducts the tours. The wet season limits visitor access to the months of late January through early August, after which the cave closes. While some level of fitness is necessary, some prior hiking experience is sufficient. Expert caving or climbing experience is not necessary. Regular bus services operate between Hue, Hoi An, and Danang, and Dong Hoi. A normal tour lasts four days and costs $3000(2,51,812.65 Indian Rupee), of which $660(55,398.78 Indian Rupee) is donated to Phong Nha Ke Bang National Park. A guide (at least one of the British cavers involved in the original exploration leads all tours), a safety assistant, cooks, porters, and a park ranger are included in every group, which has a maximum of ten guests.  The network of caves in Central Vietnam has completely changed the area. Previously among the poorest districts in Vietnam, it is currently the world's most sought-after location for cave research and the nation's fastest-growing tourism destination.

Even though the largest cave in the world may have gotten much larger, it might still grow!