Son Doong cave is located in the core zone of Phong Nha - Ke Bang National Park, Quang Binh province. Son Doong cave was discovered by Mr. Ho Khanh, a forest ranger from Phong Nha in 1990. Son Doong cave was surveyed and announced as the largest cave in the world by cave explorers from the British Cave Research Association in 2009 - 2010. Son Doong cave was opened for tourism exploration in August 2013.