The roof of Son Doong collapsed centuries ago. The sunlight and fresh air allowed a lush jungle to take root inside the cave. Here, an Australian named Ben Mitchell marvels at the landscape.
Plant Life in Cave
The giant cave contains two "daylight windows," which allow light to enter many parts of the cave. At the base of these windows are large jungles which use all the available light to nourish trees that grow almost 10 stories tall.
Giant stalagmites over 250 feet high and enormous rimstone pools are present throughout the cave.
Hope and Vision Passage
A half-mile block of 40-story buildings could fit inside the largest part of the cave, which may be the world's biggest subterranean passage.
From September to January is flooding season in the region, so there are no tours while the cave weathers the rainy season.
Sleeping Among the Stalagmites
On their first night inside the cave, visitors camp near Hand of Dog, a massive stalagmite that looks like a dog's paw.
An entire river runs inside the cave. Scientists have discovered never-before-seen plant species around Son Doong's waterfalls.
Rare cave pearls fill dried-out terrace pools inside Son Doong. They formed drip by drip over the centuries as calcite crystals left behind by water layered themselves around grains of sand.
Conquering an Infinite Drop
The man who discovered Son Doong never fully entered the cave because he feared its steep drop into what appeared to be an abyss. Next year, Oxalis Tours will take every visitor down a nearly 300-foot drop into the cave's entrance.
Vietnam's Son Doong cave, which is over 5.5 miles long and could fit a 40-story skyscraper inside its walls, was first explored by British cavers in 2009. Now, thanks to the tour company Oxalis, which has exclusive permission to run tours inside, will give the public a look at the wonders inside.