That same morning, two flights departed from Dong Hoi Stadium, flew over the central core of the ancient limestone mountain range that is more than 400 million years old, then returned to Dong Hoi.
The helicopter took off from Dong Hoi Stadium carrying journalists and leaders of Quang Binh province to start the tour. It was a spectacular space, a majestic limestone mountain range, containing more than 300 large and small caves.
Looking at the giant limestone mountains from the sky, you will understand why this place has the world's largest cave Son Doong, the world's third largest cave En, the 31.4km Paradise and many other natural wonders.
Please enjoy some photos of this flight and photos of the cave inside the limestone mountain here.
The Ho Chi Minh Trail in the eastern Truong Son passes through hills, fields and rubber forests of the people.
Then approach the high mountains, below is the Ho Chi Minh trail west of Truong Son.
The Ke Bang limestone mountain range is called PNKB National Park with a total area of over 123,000 hectares.
Most are evergreen limestone forest types. Pictured is a funnel forest growing from a sinkhole in a very unique limestone mountain.
A limestone mountain range with a cave opening seen from a helicopter.
The forest coverage here is up to 93.6%, the area of primary forest reaches over 83.7%, the National Park has the largest coverage and proportion of primary forest among the National Parks and Nature Reserves in Vietnam. The richness of geology, geomorphology, hydrology and climate factors has created for Phong Nha - Ke Bang 15 large habitat types with 10 types of vegetation.
In PNKB National Park, there exists a tropical evergreen closed forest on limestone mountains at an altitude of over 700m with an area of 22,500ha, which is the most unique forest type in Vietnam and in the world. Moreover, an area of over 1000ha of endemic limestone mountain cypress (Calocedrus rupestris) population on limestone mountains makes scientists surprised by this presence.
There are also cave forests here. Phong Nha - Ke Bang is located in the Central Truong Son region and is considered one of the 200 biodiversity centers of the world.
There are two cave systems here with more than 300 large and small caves. Including a water cave system tens of kilometers long.
The dry cave system, also known as the dome cave, is also dozens of kilometers long. Together, these two systems have reached nearly 150 kilometers of caves in 24 years of searching by British cavers and local people.
