The Exploration of Hang Son Doong

By Howard Limbert

The discovery and exploration of this wonderful cave is the highlight of the British cavers success in Vietnam. However, the cave did not give up its secrets easily. Our team had explored the huge Hang En cave in 1994 and the river that goes through this cave sinks in an enclosed valley with no way in at the sink. This is completely blocked, by rocks and trees washed in during floods that occur every year during the wet season. From where the water sinks to where it resurges was a 10km gap in the map. Hence, we knew a cave should exist in these mountains but until 2009 we had not discovered any entrance that lead to a cave.

In our previous expeditions, we had met Mr. Ho Khanh who told us about a cave in the area, which had wind and cloud blowing out of the entrance. He discovered the entrance in 1990 when he was alone in the jungle searching for valuable wood. When he was caught in a thunderstorm, he sheltered at a base of a large cliff and it was then that he discovered the entrance. He did not enter the cave, as at the entrance was a deep and difficult climb down. He however told me this story and with his help we searched for this illusive entrance. It took many years to rediscover the entrance due to the remote location and dense jungle vegetation.

When we returned to Phong Nha in 2009 we met Mr. Ho Khanh who told me he had finally found the entrance. On our caving expeditions, we have a number of teams that enter the jungle searching for new caves. I sent a team of 5 along with Mr. Ho Khanh to visit this cave and a number of other caves he had found.

During the initial exploration Hang Son Doong the main passage in Hang Son Doong was explored up to the great wall of Vietnam. This involved long and difficult trips into the cave sometimes exploring for 20 hours. As we explore new caves we make an accurate map of the cave using laser instruments for measurement. After the initial exploration other members of the expedition entered the cave to explore the lower river series as well as any side passages all of which we surveyed. Also a team visited to take some photographs of this amazing discovery. When we calculated our measurements we realised we had found something quite special and probably the largest cave in the world.

None of our team had seen any cave quite so enormous or beautiful as this cave. The two dolines in the cave are unique and allow light to enter showing the spectacular beauty of the cave.

Myself and Mr. Ho Khanh along with the head of the Ban Doong village decided on the name of the cave which translates in English to Mountain River cave.

After the discovery of the cave, much interest was generated about the discovery of the new largest cave in the world and many people wished to visit. So in 2010 we brought a National Geographic film team and photographers to Hang Son Doong. This took over 1 month in the cave to complete. As well as assisting in the film and photography the team managed to climb the difficult great wall of Vietnam , a climb of 95m. At the top of the great wall we explored another 500m of huge passage to an exit in the jungle thus completing a complete traverse of the cave.

The film and especially National Geographic magazine helped promote Hang Son Doong to the world and from this time many tourists came to visit the Phong Nha Ke bang National Park. The once very poor province of Quang Binh suddenly became famous and became a big attraction to foreign visitors.

Oxalis was formed in 2011 and we decided to come and stay in Phong Nha and try and help the local people with jobs. This was achieved with the great help of Mr. Chau A who promoted adventure tourism and large numbers of people started to make their way to Phong Nha to enjoy these adventure tours exploring caves both inside and outside the National Park. This has been an incredible success story, it has changed the lives of many local people. Instead of doing illegal activities in the jungle they now obtained jobs as porters and guides looking after tourists. Along with caves such as Phong Nha cave and Paradise cave and Dark Cave Phong Nha has grown to be one of the fastest growing tourist destinations in Vietnam.

Hang Son Doong, this magnificent cave was the main reason for the promotion of tourism in this wonderful World Heritage site.

Nowadays access to Hang Son Doong is strictly controlled to preserve this special place. Only 1,000 people per year are allowed to visit under strict control with a maximum group size of 10 people. These 10 people are looked after by a large team of safety experts and porters.

Numerous films including Hollywood have visited and filmed in the cave helping not only Quang Binh but the whole of Vietnam promoting tourism.

When we started exploring caves in Vietnam we had no idea that Vietnam would become our home. We have seen such enormous changes in the country in the last 30 years we have been exploring caves in Vietnam. We do hope that conservation continues to preserve these natural wonders of the world and the work of the British cavers will continue and maybe more amazing discoveries are still awaiting exploration deep in the Phong Nha Ke Bang National Park.