In 1991, a man named Hồ Khanh found a cavity in the Phong Nha-Kẻ Bàng park, on the coast of Vietnam, about 500 kilometers south of the capital Hanoi. As he would tell later felt a gust of wind and heard the running of a river inside. The entire park is home to numerous caves (more than 150). Because of this, and because the entrance was so hidden by undergrowth, Khanh was unable to find it a second time.
He spent years trying to rediscover it until in 2009 he managed to guide a group of cavers from the British Cave Research Associationwho explored the Son Doong Grotto for four days, between April 10 and 14.
What they found was the largest of all natural caves in the world, with a passage of 38.4 million cubic meters in volume, formed between 2 and 5 million years ago.
The length of the passage reaches 5 kilometers and is no less than 200 meters high (for comparison, the Torre de Cristal in Madrid, the tallest building in Spain, measures 249 meters and has 50 floors).
In total, the cave reaches 9 kilometers deep, it is crossed by a stream and, because the roof has collapsed into two large areas or sinkholes allowing light to pass through, a thick forest grows inside.
Due to its gigantic proportions, which would allow a city to be built inside with 40-story skyscrapers, it is also home to the largest stalagmites in the world. Some reach up to 70 meters.
The cave was extensively mapped and photographed by National Geographic in 2010, thanks to which a virtual tour can be taken online on the Son Doong 360 website.
In April 2019, a team of British divers, the same ones who participated in the rescue of the children of the Thai soccer team in 2018, discovered that the cave is connected by a tunnel (which would reach 120 meters deep) that runs underwater. with another large cavern, that of Hang Thung, which would add another 1.6 million cubic meters of volume.
Tourist access to the cave is quite restricted, with only a thousand permits per season (and prices around 2,000 euros per visit). But the feeling of visiting a lost and, in a way, cinematic world is what most of those who have been able to afford to enter report. In fact, it seems that the main theme of the Indiana Jones movies tends to be quite recurrent between the expeditions during the journey.
In addition, in the rainy season it is usually inaccessible. For this reason, the Vietnamese government is considering building a cable car that runs through the entire cave, which is opposed by environmental associations.
Son Doong 360 (National Geographic) / CNN / DailyMail / Vietnam.com / Son Doong Cave (official website) / Wikipedia.