Inside Son Doong: Conquer the World’s Largest Cave

1. When and how was Son Doong Cave discovered?

• Son Doong Cave was discovered in 1990

The natural wonder was only discovered in 2009, during an expedition led by a group of British speleologists headed by Howard Limbert. Since then, Son Doong Cave has held the record for the biggest cave in the world, dethroning Deer Cave in Malaysia.

In reality, Son Doong Cave was first found in 1990 by a local resident of Phong Nha, Mr. Ho Khanh. The cave is located within the cave complex of Phong Nha-Ke Bang, which is part of a subterranean system that includes more than 150 other caves near the border with Laos. Even though the limestone of Phong Nha-Ke Bang National Park is around 400 million years old, hang Son Doong was formed less than 3 million years ago.

As the largest cave in the world, Son Doong is one of the explored caves and caverns that make up 30% of Phong Nha-Ke Bang National Park. This underlines that there is still much to discover, as Howard Limbert points out. This reality also explains the diversity and richness of Vietnam's fauna and flora, making this region a true natural treasure to traverse in Southeast Asia.

• The discovery of Hang Son Doong, how did it happen?

While in the forest foraging for food and timber to feed his family, Ho Khanh stumbled upon an incredibly deep hole. He was struck by the gust of wind that hit his face and the sound of a river deep inside the cave. Initially, he did not venture far into the cave as he was terrified and instead returned to his village as quickly as he could. Sadly, when he tried to find the cave again later, he was unable to locate it because it was hidden by the surrounding vegetation.

It took almost two more decades for Ho Khanh to rediscover Son Doong Cave. Amazingly, in 2008, he found the cave again. In 2009, he assisted Howard and Deb Limbert, members of the British Cave Research Association, in exploring the cave. Then, in 2013, the cave was officially recognized by the Guinness Book of World Records as the world's largest natural cave.

• Why is it Called Son Doong Cave?

According to the tradition of speleologists, the person who discovers a cave has the privilege of naming it. At the end of the expedition in April 2009, the group asked Ho Khanh to choose a name for the cave. Many people suggested naming the cave after Ho Khanh to honor its discoverer.

Nonetheless, after consulting with members of the expedition, they settled on Son Doong. The two words making up this name are "Son," meaning mountain, and "Doong," which refers to a neighboring valley where the Thuong River flows and which is inhabited by the Bru Van Kieu ethnic minority. Additionally, "Doong" can mean a limestone mountain cave with an underground river flowing through it.

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2. What to Do and See at Son Doong?

Well referred to as the biggest cave in the world, Son Doong Cave stretches for about 9 kilometers, with its highest arch measuring up to 200 meters long and about 150 meters wide (big enough to hold a 40-floor skyscraper). The volume is 36.8 million cubic meters (equivalent to 15,000 Olympic swimming pools).

The formation of this intricate and extensive cave system began with rainwater infiltration from the jungle above, which gradually eroded the rocks. A dense tropical rainforest covers the lowest parts of the cave, roughly 200 meters deep, where some segments of the ceiling have collapsed. This environment supports an impressive ecosystem, with unexplored regions containing dangerous routes that require careful navigation.

• Giant stalactites

If the stalactites of Phong Nha cave make you want to go wow, then those of Son Doong would make you feel like a midget before mighty giants with big columns of stalagmites that have never been observed in other places. No one has named Hope and Vision stalagmite as the tallest in their respective countries but it may very well be close to 80 meters high (higher than Arc de Triomphe located in Paris, France). 

In fact, this massive height exceeds that which has kindomation as tallest according to Guinness inside Zhi Jin Cave situated within Chinese boarders at 70 meters apart vertically.

About two kilometers from the cave's entrance lies another monumental formation called the “Hand of Dog”, named for its resemblance to an animal’s paw. This formation, shaped by calcium-rich water droplets over thousands of years, offers a stunning view. From certain vantage points, you can see these impressive stalagmites and capture remarkable photos.

• A rainforest inside Son Doong Cave

Over time, the collapsed ceilings of the cave have created holes known as sinkholes that support exuberant vegetation, forming a remote and dangerously inaccessible jungle. Among them is an incredible sinkhole with a tropical garden called Eden’s Garden. These openings allow light to reach the cave, facilitating the growth of lush vegetation and creating a small jungle within it. An exclusive ecosystem in Son Doong Cave survives on this sunlight.

At times, access to this sinkhole is enveloped by an exhilarating, foggy, misty atmosphere. The terrain becomes even more unique and exceptional when the forest is covered by a veil of mist.

• An underground river in Son Doong Cave

As the name implies, Son Doong Cave is crossed by an underground mountain river. This river plays an essential role as a thermal regulator for the cave ecosystem. The watercourse creates multiple layers of mist within the cave and sinkholes, contributing to the mysterious atmosphere that prevails.

The underground river inside Son Doong Cave winds through spectacular waterfalls, some reaching 5 meters high, while others rise to more than 10 meters. The powerful sound of these waterfalls resonates at the very entrance of the cave. These sounds scared Ho Khanh during his first discovery of Son Doong.

>>> Check this out: Phong Nha Ke Bang National Park: The Most Beautiful Cave in Vietnam

• Caverns of "pearls"

Water droplets dropping from above are responsible for the creation of impressive “pearls” which have developed on cave floors through years. They range in size, shape and color resembling peas and baseballs.

Son Doong Cave’s pearls grow in their own puddles then brightly glow inside on rainy days when headlamps are shining. Notably, they have no intrinsic worth being just ordinary deposits of calcium carbonate. When outside or sunlight hits them, they lose their shine and become discoloured because they dry fast.

• A gallery of fossils

The limestone present in the Quang Binh region is a sedimentary rock that was formed more than 400 million years ago. This rock is the result of billions of dead marine animals, such as fish, corals, snails, and many others. At the time, the region was home to a shallow ocean where these marine organisms could thrive.

When millions of years went by many animals perished; their bones and shells turned into what we now call sedimentary rocks. In other instances, shells or bones did not get compacted into the rocks but were instead preserved as fossils through mineralization process. It is the passageways of underground river excavated by Son Doong Cave that have shown these fossils on its walls and ceilings today.

• A Great Wall of Vietnam

During exploration in 2009, the expedition team came across a gigantic calcite formation that blocked all paths. Lacking the specialized equipment to climb this giant wall, they decided to turn back. At the time, no one knew what was behind this imposing stalagmite, so they called it the Great Wall of Vietnam to describe its impressive character.

In 2017, Quang Binh province installed an 18-meter-high stainless steel staircase at the lowest point of the Great Wall of Vietnam, along with several safety ropes on the other 65 meters of the wall. This presents one of many challenges faced by the expedition crew in Son Doong Cave.

On the other side of the Great Wall of Vietnam is a lake about 500 meters long. After it rains, water fills this passageway, forming a light green-colored lake. During periods when the lake is full, visitors use rafts or boats to navigate its waters.

3. Is it Possible To Visit The Cave?

The Son Doong expedition circuit was launched in Vietnam in August 2013 and quickly became the most sought-after adventure itinerary for enthusiasts from all over the world.

However, if you plan to visit Son Doong, it’s important to know that it cannot be explored on your own. The law prohibits any individual or group from exploring the cave without permission from the Phong Nha-Ke Bang National Park board of trustees.

Only one company is authorized to organize expeditions in Son Doong, and that company is Oxalis. Therefore, if you want to explore the cave, you must contact them. The Oxalis website lists the current price of an expedition to Son Doong at around $3,000 USD per person, depending on the season.

When registering for the visit, all participants are required to fill out a medical questionnaire, indicating whether they have high blood pressure, heart disease, asthma, or joint problems that may affect their visit.

You can find more information about the “Son Doong Cave Tour” on their website: Oxalis Adventure.

4. How to Visit Son Doong Cave

The only way to access Son Doong, the largest cave in the world, is to first go through the forest, passing through Ban Doong, a small village of the Bru-Van Kieu ethnic minority community. From Ban Doong, you continue into the forest of Phong Nha-Ke Bang National Park until you reach Hang En, the third largest cave in the world, which also serves as the entrance to Son Doong Cave. The journey to conquer Son Doong lasts 6 days and 5 nights, covering 17 km of jungle, 8 km of caving, a steep climb of 800 meters, and a 90-meter climbing rope on the Great Wall.

According to cave experts, visiting Son Doong is not as difficult as many people think. If you have never participated in such climbing expeditions, you should prepare seriously a few months before departure. Exercises can include walking 10 km in a few hours and overcoming at least one hill of approximately 300 to 400 meters.

It is also recommended to train on rough and rugged terrain, doing at least 6 hikes of 10 km and at least one large hill in the 3 months prior to the expedition. It is essential to carry suitable shoes, backpacks, and the necessary items indicated to be well prepared for the trip.

Having experience in trekking and adventure travel is a plus. The trip to Son Doong demands a lot of physical strength. You have to move constantly during the day, sleep in tents, and use outdoor toilets. Therefore, previous experience in trekking or adventure trips will help you adapt more easily to this experience.

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5. What is the best month to visit Son Doong Cave

The Son Doong - Phong Nha region experiences four climatic seasons a year (spring, summer, autumn and winter), as do many provinces in northern Vietnam. For reasons of weather and visitor safety, especially during the rainy season, visiting Son Doong is only possible from January to the end of August each year. 

From September to December, Son Doong Cave is closed to tourism and exploration activities to ensure safety and allow for ecosystem restoration. Therefore, you can refer to the following periods to choose the time that suits you best:

• January - March: The air in Phong Nha is still fresh when you walk all day through the forest. It is the time when the mountains and forests are green and growing.
• April - May: Phong Nha enters a period of transition, with mild, light sunshine and sporadic rainfall. It is a good time to go hiking without worrying too much about the weather conditions.
• June - August: These are the hot summer months, but most of the time, visitors move inside the cave. The temperature inside the cave varies between 22 and 25 °C. During this summer period, visitors can even bathe freely in the underground streams and lakes during the exploration of Son Doong.

>>> More weather information: Best time to travel to Viet Nam: Tips from locals

6. Where To Stay?

After finishing your Son Doong Cave adventure, you can also combine your visit with other attractive tourist sites in Quang Binh. Don’t forget to explore the unique culinary culture of central Vietnam, which features exceptionally appetizing specialties from Quang Binh.

To live a complete experience, where you can have fun, explore as much as you want and taste delicious dishes, it is also important to choose an accommodation that suits you for a perfect trip. Below, we recommend excellent places to stay:

• Son Doong Bungalow
• Ho Khanh's Homestay
• Chay Lap Farmstay
• Areca Bungalow
• Grapefruit Homestay
• Thao Nguyen Homestay
• Victory Road Villas
• Oxalis Home

These establishments offer quality accommodation and attentive service to ensure your stay is as pleasant as possible.

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Conclusion

If you are passionate about adventure travel and love to explore, visiting Son Doong Cave in Quang Binh, Vietnam will undoubtedly be a memorable and meaningful experience in your life. This is one of the best travel destinations on the planet, especially for adventurous travelers and exploration enthusiasts. You will have the chance to touch a natural masterpiece recognized as one of the most magnificent places on Earth.

As a local travel agency with over 15 years of experience in designing custom tours, Kampa Tour is confident in creating a Vietnam travel itinerary featuring Son Doong Cave or alternatives in Phong Nha-Ke Bang that are most suitable for you. Contact us now!

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