Interesting

There are many things that make the Son Doong Cave in Vietnam a remarkable natural wonder; at about 9km in length, 200m in width and 150m in height, it is the largest cave in the world, with caverns capable of fitting entire city streets and skyscrapers. It is home to a river, jungles, and entire cave ecosystems. Only slightly less remarkable is the fact that, until 2009, we did not even know how grandiose and impressive Son Doong (or Mountain River) Cave really is.
     The cave was found in 1991 by local man Ho Khanh. In 2009, a group of British cavers led by Howard Limbert explored the cave’s interior, only then realizing that it was possibly the greatest cave in the world. Son Doong Cave has dethroned Malaysia’s Deer Cave as the world’s largest.
     The water and limestone that carved it over millions of slow, patient years have created spectacular and unique formations. Occasional collapses in the roof have allowed underground jungle ecosystems to form, and with them, all-new species that have never been seen anywhere else. Rare cave pearls, ancient fossils, and towering stalactites form around a river running through the caves, which are so large that they form their own clouds.
     Now that the caves have been thoroughly explored, the government has granted tour operators permission to host treks through the caves, which have already begun operating this summer. A visit will set you back at least USD $3,000.

The cave was first discovered by local man Ho Khanh when he was a child. At the time, he had to wander the jungle to find food, and used the caves to hide from bombs and from the rain. Although he forgot where he had found the cave, he was able to locate it again later. However, the descent he had found was too steep for him to take.

A team of British explorers, lead by Howard Limbert, first descended into the cave in 2009. Little did they know that they were the first to explore the largest known cave in the world.