Hang Sơn Đoòng – It is located in the Phong Nha-Kẻ Bàng National Park in Vietnam, which contains the oldest karst system in Asia, between 400-450 million years old.
It has a depth of 150 meters and a distance of 9 kilometers.
There are two gateways and a river that flows from the inside is amazing. The cave was seen by a farmer in 1991 but has not spread to the world. However, after a tour of British and Vietnamese expeditions in 2009, it was discovered to be the largest cave in the world.
It is now a popular land area and costs $ 3,000 per person for one trip. Traveling here during the rainy season is risky. The cave, which covers an area of 9 km of thick forest, is also rich with animals.
This is a great boost to the Vietnamese tourism industry. Tourists from all over the world come here annually. This is a very special ecological zone and it is the duty of the public to protect it.