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By Tra My

 Son Doong is the world’s largest cave in Vietnam’s Quang Binh Province. It was discovered in 1991 by Ho Khanh, a local inhabitant, when he was seeking shelter from the rain. Not until 2009, when the British Royal research team led by Howard Limbert joined the adventure, did the world officially hear of this breathtaking cave.

Son Doong fever exploded following ABC News’ coverage of the discovery on Good Morning America. All of a sudden, Son Doong was a dream destination for fans of extreme adventure. Shots of Son Doong that were constantly updated from adventure teams prompted a special interest from domestic and international tourists in the cave dubbed “a heaven on earth.”

In 2013, Guinness World Records said Son Doong was the world’s largest cave however in 2014 there was some debate over its length, width, height and volume. One year later, Guinness World Records confirmed it was the world’s largest cave in volume (38.5 million cubic meters).

The discovery of Son Doong is full of fascinating anecdotes. Ho Khanh, who was searching for agar wood in the forest, was stuck in a large hurricane. Fearing a flood, he sought shelter. Fortuitously, he found refuge in Son Doong Cave. The cave was unnamed at the time, and an exploration team and Mr. Khanh proposed some options, finally coming up with Son Doong. Son means “the mountain,” and Doong was the location where the cave was discovered. Another option was to name it after the discoverer, Ho Khanh.

Not realizing the historic moment, Mr. Khanh gave up agar wood searches and switched back to farming. For 15 years, traces of the world’s largest cave sank into oblivion. In 2006, Mr. Khanh met the British Royal Cave Research team assisting in its search for new caves in Quang Binh. He recounted his story to the team.

The search for the old cave was not successful initially. In his memory, the cave was so huge and winds kept roaring out from inside, he was frightened at the thought of monstrous pythons slithering from within the cave. He dared not venture into the cave but hid by a rock until the rain was gone.

Mr. Khanh led the team in search for many days to no avail. Howard Limbert, observing the natural phenomenon in the surrounding area, confirmed there must have been a huge cave around. However, time had run out and the research team had to fly back to England. Before heading back home, Mr. Limbert asked Mr. Khanh to try to figure out the whereabouts of the cave.

In mid-2008, Mr. Khanh ventured into the woods on his own and approached Doong hamlet. After spending a night in the forest, Mr. Khanh remembered his feeling of “chills roaring out from within the cave.” This time, he did not fear “monstrous pythons” because he realized it was a natural phenomenon. In 2009, Son Doong became known all over the world.

According to geologists, Son Doong Cave was formed two to five million years ago when rivers that crossed the cave were buried under a fault line. The current created a giant tunnel. Son Doong Cave measures at least 5 km, or the length of 68 Boeing 777 aircraft. The number is possibly even larger because even with today’s state-of-the-art technological tools scientists are still not yet able to ascertain the actual length of the cave.

Son Doong Cave is also famous for its biodiversity. Discoverers found it filled with a primordial forest completely untouched by humans. Deep within the cave are a perennial forest, undercurrents and stalactites. The climate is separate from outside weather. Internal clouds make it look like a heaven only found in movies with superb visual effects. When daylight comes, millions of sun rays dapple the cave, creating a captivating light effect. Experts have even named this internal forest “Eden” in honor of its impeccable enchantment.