Inside world of Son Doong – the world’s largest cave Pictures of Son Doong Cave have covered newspapers worldwide, showing the "attraction" of the world's largest cave. Son Doong Cave in Quang Binh province, central Vietnam, was worldwide known in 2009, when a group of British explorers and locals discovered the whole cave. Since then, the world has been surprised by spectacular scenery of the vast cave with a length of more than 9 km, with forests, rivers, stalagmites... All are inside the Son Doong cave, the world's largest cave. To enter the cave, explorers had to use ropes to drop down 80m depth to begin the journey to explore the world in Son Doong cave. Four years after the cave was revealed to the world, the tour to conquer Son Doong cave was tested in August, opening up the opportunity to explore the cave for tourists. The test will continue in February and March 2014. Each group of tourists will have up to six people, with the cost of $3,000. More than 100 international visitors have registered for the tours in 2014. The entrance to the Son Doong cave. Photo: Huffington Post. Part of the cave roof collapsed a few centuries ago. Thus, rain and sunlight can reach here, creating favorable conditions for plant growth in the cave. Photo: Huffington Post. An explorer enters into the cave. Photo: sondoongcave. Green vegetation inside Son Doong. Photo: Huffington Post. Trees along the entrance to the cave. Photo: Medavia. The rocks named Chan Cho (dog foot) near the cave entrance. This large stalagmite is in the shape of a dog foot. Photo: Huffington Post. Ken (cocoon) Cave with a narrow lake. Photo: sondoongcave. A different perspective of the Ken Cave. It looks like mysterious eyes. Photo: soondoongcave. The stalagmites. Photo: Medavia. A stream inside Son Doong. Photo: Huffington Post. Wading through a stream. Photo: sondoongcave. A waterfall in the cave. Photo: Huffington Post. Exploring the cave like doing the journey to the underground world. Photo: Huffington Post. A tree in the cave. Photo: Medavia. View from the Edam garden. Photo: Oxalis Fanpage. The calcareous water droplets dripping, gradually forming "pearls" in the Son Doong cave. Photo: Medavia. Rock veins covered with green algae. Photo: Huffington Post. The "exotic sculpture" of nature. Photo: National Geographic. Climbing in the Loong Con cave. Photo: sondoongcave. A large gate at the mouth of the cave. Photo: sondoongcave. The scene is flooded with light. Photo: sondoongcave. Two British explorers Howard and Deb Limbert in the journey to discover the world's largest cave. Photo: Medavia. A tree in the cave. Photo: LiveScience. The camps of the first tourist group who were allowed to explore the Son Doong cave in August 2013. Photo: Ryan Boodt. A river in the cave. Photo: soondoongcave. Pha Le, VietNamNet Bridge