Asia, Vietnam, North Central Coast, Quang Binh province, Bố Trạch district, 6 hours walk through the jungle south from Truong Son Highway
Name in Vietnamese:
Hang Sơn Đoòng (Mountain River Cave)
˜ 9,000 m
up to 150 m
UNESCO World Heritage status:
located in "Phong Nha-Ke Bang National Park", 2003, No.951
The largest known cave in the world by volume is Son Doong Cave in Vietnam. This cave is one of the great natural wonders of the world.
Location and formation
Son Doong Cave is located in Phong Nha-Ke Bang National Park - UNESCO World Heritage monument. This national park is protecting the unique nature of Phong Nha/Ke Bang Karst plateau - one of world's largest limestone karst areas, formed in Carboniferous/Permian limestone. Limestone shields here are criscrossed by giant caves, such as the Phong Nha cave (known length 44.5 km) with world's longest known cave river and the gorgeous Paradise cave (31.4 km). Total length of known cave passages here exceeds 100 km. This karst plateau continues into neighboring Laos, Khammouane Region, where also are found giant caves, such as the amazing Khoun Xe Cave.
Son Doong Cave has formed in fault zone, where a river was captured, e.g. its stream went underground. Analysis of sediments show that cave formed at least 2 million years ago but it is possible that it is much older. The giant cave has lasted for millions of years thanks to the high strength of rocks.
Local man Hồ-Khanh as a teenager discovered the entrance in Son Doong Cave in 1991. It is not that easy to find this cave in the rugged terrain of Ke Bang jungle - contrary to several other cave entrances in this region, Son Doong Cave starts as a comparatively small hole. Through this hole could be heard the whistling sound of wind and roar of fiery stream inside the cave. Hồ-Khanh did not enter the cave - it was too steep and the prospects to fall into roaring darkness was not too attractive to him.
He returned here much later, in 2009, together with an expedition of British Caving Association. This group was led by Howard and Deb Limbert who were surveying the area with the assistance of Hồ-Khanh and finding many new caves.
Exploration of Son Doong Cave was risky - group had to traverse the powerful cave river several times but they were rewarded by discovery of one of world's most amazing natural landmarks.
Description of the cave
The most amazing feature of Son Doong Cave is an enormous, giant passage in the central part. This passage is more than 5 km long, up to 200 m high and 150 m wide. In most places it is at least 80 m wide and 80 m high and there is a long section where its is wider and taller than 140 m. Cave has its own climate, often there are clouds inside. Thanks to this passage Son Doong is the world's largest cave, surpassing Deer Cave in Malaysia. Measurements of Son Doong Cave have been made with laser measuring devices.
At the far end of this passage is located the spectacular Great Wall of Vietnam - steep, muddy and slippery vertical wall which hindered further passage in 2009. It was traversed in 2010, when researchers reached the end of the cave. Nevertheless there remain uncharted side passages.
Son Doong Cave has two major opening in the ceiling - sinkholes. One is called Watch Out for Dinosaurs, as it reminds another world from long times ago. Here in the cave falls very tall waterfall. The other sinkhole, which is covered with lush jungle, is called Garden of Edam (ironic reference to the beautiful Garden of Eden in Sarawak, Malaysia). By the way - researchers has to be careful as the cave is infested by poisonous centipedes. Researchers have noticed that monkeys enter through these sinkholes to devour snails in the cave.
Stalagmites in this cave may tbe the tallest in the world, exceeding the 70 m height. One such giant is called Hand of Dog as it resembles paw of this animal.
Behind the Great Wall of Vietnam researchers found also giant gours - rimstone pools. These gours now are dry and covered with green moss. Here they found also some of the largest cave pearls in the world - as large as grapefruits. These pearls are created by dripping water and their giant size could be ecplained by the big distance of falling from the tall ceiling.
Is there place for tourists?
Visit to Son Doong Cave is overwhelming to feelings. When one enters the giant cave room in places further away from the underground river, the eerie silence and invisible walls and ceiling (common headlights do not reach that far) create unique experience. Not less impressive are the sinkholes with misty jungle, the cave waterfalls, stalagmites, pearls... Sounds like a perfect place to develop tourism.
At the same time cave environment is very fragile. Son Doong Cave is that unique that it would be a huge loss if this fragile beauty would be lost forever.
Authorities in Vietnam seem to be indecisive about the development of tourism here. Meanwhile some businesses are active. In 2013 the first group of tourists arrived in the cave. These were not the ususal tourists - trip required to abseil 80 m in to the sinkhole and costs from each participant were 3,000 USD. Such high-end adventure tourism could bring much benefit for local community... but who knows how this will affect the cave environment.