Hang Sơn Đoòng

Discovery

The entrance to Hang Sơn Đoòng was found on December 10, 1990 by a local man named Hồ Khanh, while searching for agarwood, a valuable timber. Although he initially went to investigate further, he was discouraged upon approach by the sound of rushing water and the strong wind issuing from the entrance. Not thinking it to be of any great importance, by the time he returned to his home, he had forgotten the exact location of the entrance. Later, he mentioned his discovery in passing to two members of the British Cave Research Association (BCRA), who were exploring in the local area. They asked him to attempt to rediscover the entrance, which he eventually managed to do in 2008, and in 2009, he led an expedition from the BCRA to the entrance.

This expedition, conducted between April 10 and 14, 2009, performed a survey of the cave and gave its volume as 38,500,000 m3. They estimated that the overall length of the cave system exceeded 9 km.

Description

Formed in Carboniferous/Permian limestone, the main Sơn Đoòng cave passage is the largest known cave passage in the world by volume – 3.84e7 m3, according to BCRA expedition leader Howard Limbert. It is more than 5 km long, 200 m high and 150 m 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 and is punctuated by two large dolines, areas where the ceiling of the cave has collapsed. The dolines allow sunlight to enter sections of the cave, resulting in the growth of 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. This increases the potential volume of the cave by more than 1,600,000 m3.

The cave contains some of the tallest known stalagmites in the world, which are up to 80 m tall. Behind the Great Wall of Vietnam were found cave pearls the size of baseballs, an abnormally large size. The cave's interior is so large that it could fit an entire New York block inside, including skyscrapers, or could have a Boeing 747 fly through it without its wings touching either side. File:Son Doong Cave Doline with Scale.jpg|Sơn Đoòng cave doline File:Son Doong Cave 1.jpg|Another view out the mouth of the cavern, showing the rainforest in its doline File:Son Doong Cave 6.jpg|Reflecting pool further inside File:Son Doong Cave DB (1).jpg|Large stalagmites in the passage of Hang Sơn Đoòng in Vietnam: The tallest has been measured at 70 m in height. File:Son Doong Cave DB (2)-edited.jpg|Large stalagmites in Hang Sơn Đoòng: This passage is said to have the greatest cross-sectional area of any cave in the world. File:Son Doong Cave DB (3).jpg|The massive second doline in Hang Sơn Đoòng is so large that trees grow inside.

Tourist activities

In early August 2013, the first tourist group explored the cave on a guided tour at a cost of US$3,000 each. Permits are required to access the cave and are made available on a limited basis, from January to August. After August, heavy rains cause river levels to rise, making the cave largely inaccessible. , only Oxalis Adventure Tours have permission to enter the cave for tourism purposes.

Development plans

Plans were considered to build a cable car through the cave. The proposed system would be 10.5 km long, and cost between US$112 and $211 million. However, the plans were opposed by environmentalists and locals because of the damage mass tourism could cause to the cave and local environment. The plan was ultimately cancelled by local government.

References

References

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