Only from August last year have tourists been permitted to visit the cave. Since then, It has made headlines in prestigious magazines and on television channels, including in the National Geographic in 2011.
According to Deputy Director of the provincial Department of Culture, Sports and Tourism, Nguyen Van Ky, tours to the cave last for seven days and six nights at a cost of US$3,000.
Due to the adventurous nature of the trips, each travel company is permitted to launch only four tours per month and each of the tours will have a maximum of eight visitors assisted by tens of tourism workers, he said.
Apart from tours to Son Doong, Quang Binh province is also seeing tourists to Rao Thuong-Swallow cave, Dark cave-Mooc spring and Sinh Ton valley-Aquarium cave.
Son Doong cave, which scientists say to have been created two to five million years ago, was first discovered in Phong Nha-Ke Bang National Park by a local man in 1991.
The cave was later made public in 2009 by a group of British scientists from the British Cave Research Association after their surveying trip in the park.
Son Doong is 6.5 kilometres long and is estimated to be 200 metres in width and 150 metres in height. With its largest chamber judged to be 250 metres in height, the cave is said to have enough space to accommodate 40-storey skyscrapers.
