After British Cave Research Association, there are 2 other organizations recognized Son Doong is the largest natural caves in the world.
At evening June 17, at the Opening Festival of Quang Binh Province, 2017, World record Union and World Record Association recognized Son Doong is the largest natural cave of the world at the same time, the cave is located in Son Trach Commune, Bo Trach District.
Son Doong Cave was discovered by British Cave Research Association and announced as the largest caves of the world in 2010.
Son Doong was created about 2-5 million years before when the river water flows through the limestone area buried along a fault line. The water line eroded and created a huge underground tunnel under the mountains. The cave has a width of 150 meters, 200 meters tall, its length is up to 9 kilometers, estimated cave capacity is 38.5 million m3.
Besides, Song Doong Quang Binh Province has Phong Nha Ke Bang is the only heritage site in Southeast Asia recognized by UNESCO twice.
The Caves Festival 2017 with the theme : 'Kingdom of the Caves: Magnificence–Legendary' with the aim to introduce more than 300 caves in Quang Binh. In the time of the festival, Quang Binh discount about 20 – 30 percent for the entrance fee ticket to visit Phong Nha, Tien Son, Paradise Cave and discount 10 – 20 percent for accommodation and food & beverage services.