It’s strange that nobody even knew the cave existed until 1991 when it was discovered for the first time by a local native named Ho Khanh, who didn’t even dare to go in because the entrance was too steep. It was rediscovered to the world by a group of British explorers (cavers) in 2009. When setting foot in the 8.8 km (5.5 miles) cave the Brits first came upon a giant chamber 4.8 km long, 198 meters high and 150 wide – dimensions that already transcend all previous discoveries.
The cave is so big that it actually has its own river, waterfalls and a jungle.
Just for the record, the longest cave in the world is the Mammoth Cave in Kentucky (400 miles of passageways) and deepest Krubera Cave (2.197 meters/ 7.208 ft) in the nation of Georgia.