Hang Son Doong Cave

Hang Son Doong is a cave located within the boundaries of Phong Nha-Ke Bang National Park in Quang Binh Province, Vietnam, and is recognized as the world’s largest natural cave. With a volume of 38.5 million cubic meters, it was officially certified by Guinness World Records in 2013.

Cave was discovered in 1990 by Ho Khanh, a local farmer, while seeking shelter from a storm during a hunting expedition in the Phong Nha forests. However, due to the challenging land conditions, its location was forgotten until it was rediscovered and meticulously mapped in 2009 by a team of British cavers led by Howard Limbert.

The name “Son Doong” consists of two words: “Son” means “river” while “Doong” is the name of the valley where the cave is located. This valley is inhabited by the Bru Kieu ethnic minority and is the source of the Thuong River. Additionally, “Doong” also refers to a cave containing an underground river within limestone mountains.

Hang Son Doong Cave (Source: Local Vietnam)

Physical Characteristics

Hang Son Doong is larger and more unique than any other cave in the world in terms of size and internal structure.

• Total Length: 9.4 km
• Width: 175 metres
• Height: 503 metres
• Volume: 38.5 million m³

With this size, it is five times larger than the Deer Cave in Malaysia, which previously held the title of the world’s largest cave with a volume of 9.5 million m³. Inside, there are spaces wide enough to accommodate 40-story skyscrapers.

Ecosystem and Geological Structure

One of the most remarkable features of Hang Son Doong is its own internal ecosystem and microclimate. The cave’s interior structure creates a unique air circulation and cloud formation due to water seeping in from above and air movement within the cave. This situation results in constantly changing atmospheric conditions inside the cave.

• Large collapse areas (dolines): These allow sunlight to enter the cave, enabling the development of a unique rainforest ecosystem within.
• Massive stalactites and stalagmites: Enormous limestone formations reaching over 80 metres in height.
• Underground river and lakes: A river flows through the cave, yet remains partially unexplored, with some sections submerged underwater.
• Endemic cave species: Blind fish, freshwater shrimp, bats, monkeys and exotic bird species live inside and around the cave.

Hang Son Doong Cave (Source: Local Vietnam)

Special Features of Hang Son Doong

In addition to its immense size, Hang Son Doong contains unique natural formations not found elsewhere. Among the most notable are:

• Watch Out for Dinosaurs: A large collapse area distinguished by its vegetation and geological features.
• Garden of Edam: An ecosystem formed within a massive collapse area, hosting one of the largest forests inside the cave.
• Cave Pearls: Large calcite spheres formed by the accumulation of sand and minerals in certain parts of the cave.
• Underground Waterfalls and Lakes: Natural water basins formed within specific sections of the cave.

Significance of Hang Son Doong in Terms of Exploration and Tourism

Recognized by Guinness World Records in 2013 as the world’s largest natural cave, Hang Son Doong has become a major destination for explorers and nature enthusiasts. However, due to its fragile ecosystem, the Vietnamese government permits only a limited number of visitors.

• Cave tourism is organized exclusively by Oxalis Adventure.
• Annual visitor capacity is capped at 1,000 people.
• Tours last four days and three nights and cost approximately USD 3,000 per person.
• Mass tourism has been prohibited to protect the cave, and a sustainable tourism model has been adopted to prevent environmental damage.

To visit Hang Son Doong, travelers must fly to Dong Hoi, the nearest close city, and then travel by road to Phong Nha-Ke Bang National Park.