Hang Sơn Đoòng

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Lore & Background

The entrance to Hang Sơn Đoòng was found on December 10, 1990, by a local man named Hồ Khanh while searching for agarwood. He initially investigated but was discouraged by the sound of rushing water and strong wind from the entrance, and later forgot the exact location. He mentioned his discovery in passing to two members of the British Cave Research Association (BCRA) exploring the area. They asked him to rediscover the entrance, which he managed in 2008. In 2009, he led a BCRA expedition to the entrance. That expedition, conducted between April 10 and 14, 2009, surveyed the cave and gave its volume as 38,500,000 m³ (1.36×10⁹ cu ft). Their progress was stopped by a large, 60-meter (200 ft) high flowstone-coated wall, which they named the Great Wall of Vietnam. The expedition returned in March 2010 and successfully traversed the wall, reaching the end of the cave passage. They estimated the overall length of the cave system exceeded 9 km (5+1⁄2 mi).

Reader's Guide

Hang Sơn Đoòng is the largest known cave passage in the world by volume – 3.84×10⁷ m³ (1.36×10⁹ cu ft), according to BCRA expedition leader Howard Limbert. It is more than 5 kilometers (3.1 mi) long, 200 meters (660 ft) high, and 150 meters (490 ft) wide. Its cross-section is believed to be twice that of the next largest passage, in Deer Cave, Malaysia. The cave runs for about 9 km (5.6 mi) and is punctuated by two large dolines where the ceiling has collapsed, allowing sunlight to enter and support trees and other vegetation. By mid-2019, the cave was found to be connected by its underground river with a nearby cave called Hang Thung, increasing the potential volume by more than 1,600,000 m³ (57,000,000 cu ft). The cave contains some of the tallest known stalagmites in the world, up to 80 m (260 ft) tall, and behind the Great Wall of Vietnam were found cave pearls the size of baseballs. The interior is so large it could fit an entire New York block including skyscrapers, or allow a Boeing 747 to fly through without its wings touching either side. Since 2017, only Oxalis Adventure Tours has permission to enter the cave for tourism purposes. The cave is closed to all tourism activities from September to December each year for safety during the monsoon season and to allow ecosystem restoration.

Did You Know?

• The cave's name, Hang Sơn Đoòng, translates from Vietnamese as 'cave of the mountain behind Đoòng,' where Đoòng is the name of a Vân Kiều village.
• The entrance was discovered on December 10, 1990, by a local man named Hồ Khanh while searching for agarwood.
• The 2009 BCRA expedition measured the cave's volume at 38,500,000 m³ (1.36×10⁹ cu ft).
• Behind the Great Wall of Vietnam, explorers found cave pearls the size of baseballs.
• By mid-2019, the cave was found to be connected by its underground river to Hang Thung, increasing its potential volume by over 1,600,000 m³ (57,000,000 cu ft).