Explorers find world's largest cave in Vietnam.

Explorers have discovered a cave that is much larger than the world’s biggest known cave.

Son Dong cave is in the Phong Nha-Ke Bang grotto system in central Quang Binh Province.

The main vault of Son Dong is five kilometers in length, 200 meters high and 150 meters wide, said a member of the British Cave Research Association team that searched the area from April 10 to 14.

Meanwhile, the size of Deer Cave, the world’s current largest cave in Malaysia, is just two kilometers long, 100 meters high and 90 meters wide.

The exploration team said they traveled through the main vault and only a little way further, about 6.5 kilometers in total, as there was a large amount of fast-flowing water inside Son Dong.

The team is expected to officially report their discovery to the local government on April 23. They will then carry out a further exploration of the cave.

The Son Dong is below another cave in Phong Nha-Ke Bang and the entry of the cave is difficult to traverse.

It took the explorers six hours to walk the 10 kilometer forest path from Truong Son Highway to the mouth of Son Dong cave.

The cave was discovered by a local man named Khanh in 2008 but only since the British team’s exploration of the cave in April has it called the world’s largest.

Phong Nha-Ke Bang grotto system belongs to the Phong Nha-Ke Bang National Park. It is a limestone region of 2,000 square kilometers in Vietnam which borders another limestone area in Hin Nammo in Laos.

Phong Nha-Ke Bang area has 300 caves and grottos, with a combined length of about 70 kilometers.

Only 20 have been surveyed by Vietnamese and British scientists.