A stunning lake leads to the exit of Hang Son Doong, the highest (more than 200 meters or 656 feet) and widest (more than 150 meters or 492 feet) location, which is used as a basis to determine that Son Doong is the largest cave in the world. Hang Son Doong is located in the core zone of Phong Nha-Ke Bang National Park, a UNESCO World Heritage site in Quang Binh Province, central Vietnam.