Son Doong Cave is located in Phong Nha-Kẻ Bàng National Park in Vietnam. It is the largest cave in the world, measuring over 5.5 miles (9 kilometers) long and reaching heights of 650 feet (200 meters) in some areas. Discovered in 1991, it features a unique ecosystem, including its own weather system and a river flowing through it. The cave was formed around 2 to 5 million years ago by the erosion of limestone. Its vast chambers contain stunning rock formations, including stalactites and stalagmites. Son Doong Cave attracts adventurers and researchers alike, offering guided tours to explore its breathtaking beauty.