The karst formation of Phong Nha-Ke Bang National Park has evolved since the Palaeozoic (some 400 million years ago) and so is the oldest major karst area in Asia. Subject to massive tectonic changes, the park's karst landscape is extremely complex with many features of geologic significance, and many cave formations such as stalactites and stalagmites. The vast area, extending to the border of the Lao People's Democratic Republic, contains spectacular formations including 65 km of caves and underground rivers. The Phong Nha caves are reached through a pleasant river journey starting in the village of Son Trach. The visits include one cave that is reached through an underwater river, and one cave that is reached after climbing many steps into one of the karstic hills. Besides being the largest and most beautiful cave in Vietnam, the area has been used as sanctuaries for centuries. Phong Nha-Ke Bang National Park is a UNESCO World Heritage Site.

The over 200,000 ha of parkland includes beautiful limestone formations, grottoes and caves, and boasts lush forestland covering 95 percent of the park area.

The area is considered a paradise for researchers and explorers of grottoes and caves, and Vietnamese and British scientists have so far surveyed 20 with a total length of 70km. Of them, 17 are in the Phong Nha area and three in the Ke Bang Area.

The Phong Nha Grotto itself which lends its name to the whole system is probably the most beautiful of all, containing many fascinating rock formations, enchanting visitors with evocative names such as Lion, Fairy Caves, Royal Court and Buddha.

Besides the grotto and cave systems, Phong Nha has the longest underground rivers, the largest caverns and passageways, the widest and prettiest sand banks, and the most astonishing rock formations in the world.

According to initial statistics, the primitive tropical forest in Phong Nha - Ke Bang houses 140 families, 427 branches, and 751 species of high-rated plants, of which 36 species are endangered and listed in the Vietnam Red Book. The forest is also home to 32 sets, 98 families, 256 races and 381 species of four land backboned animals. Sixty-six animal species are listed in the Vietnam Red Book and 23 other species in the World Red Book.

Phong Nha - Ke Bang also boasts dozens of mountain peaks of over 1,000 metres still unexplored by men and seen as ideal sites for activities like climbing and exploration. Worthy of note are Peak Co Rilata with the height of 1,128m and Peak Co Preu, 1,213m. Lying between these peaks are valleys which promise tourists exciting eco-tours.

In addition to the diversity in the ecosystem, Phong Nha - Ke Bang is home to archeological and historical relics, such as an ancient hieroglyphic script of the Cham ethnic minority, King Ham Nghi's base built for the resistance war against French colonialists in the late 19th century, and the Xuan Son ferry station, Ho Chi Minh Trail and Road 20 used during the US resistance war.

Central Quang Binh Province has poured heavy investment into upgrading the Phong Nha - Ke Bang visitor site to turn it into the country's major tourist destination.

It's remarkable for its thousands of metres of underground passageways and river caves filled with abundant stalactites and stalagmites. In November and December the river is prone to flooding and the underground cave may be closed.

In 1990, a British caving expedition explored 35km of the cave and made the first reliable map of Phong Nha's underground (and underwater) passageways. They discovered that the main cavern is nearly 8km long, with 14 other caves nearby.

Phong Nha means ‘Cave of Teeth’, but, unfortunately, the ‘teeth’ (or stalagmites) that were by the entrance are no longer there. Once you get further into the cave, it's mostly unspoiled. There's also a dry cave in the mountainside just above Phong Nha Cave. You can walk to it from the entrance to Phong Nha Cave (10 minutes) - look for the sign to Tien Son at the foot of the stairs.

The Chams used the cave's grottoes as Hindu sanctuaries in the 9th and 10th centuries; the remains of their altars and inscriptions are still here. Vietnamese Buddhists continue to venerate these sanctuaries, as they do other Cham religious sites.

More recently, this cave was used as a hospital and ammunition depot  during the American War. The entrance shows evidence of aerial attacks. That US war-planes spent considerable time bombing and strafing the Phong Nha area is really hardly surprising: this was one of the key entrance points to the Ho Chi Minh Trail. Some overgrown remains of the trail are still visible, though you'll need a guide to point them out to you.

You should he aware that Phong Nha is heavily visited by Vietnamese groups. The cave itself is fantastic, the experience less so. That is unless you like your World Heritage sites to incorporate litter, noise, people climbing on stalagmites and cigarette smoke in the underground caverns Of course these things are prohibited, but enforcement appears to be lax to say the least. Presumably these distractions can be avoided if you arrive early in the morning. The toilets might be less putrid then, too.

The Phong Nha Reception Department, an enormous complex in Son Trach village, organises tourist access to the cave. You buy your admission ticket here and organise a boat to take you to the cave. Boats seal about 10, so it's cheaper to share. The cave system is electrically lit, but you may want to bring a torch (flashlight), as some of the paths are poorly illuminated.

Brief description

The karst formation of Phong Nha-Ke Bang National Park has evolved since the Palaeozoic (some 400 million years ago) and so is the oldest major karst area in Asia. Subject to massive tectonic changes, the park’s karst landscape is extremely complex with many geomorphic features of considerable significance. The vast area, extending to the border of the Lao People’s Democratic Republic, contains spectacular formations including 65 km of caves and underground rivers

Justification for inscription

Criterion (viii): Phong Nha is part of a larger dissected plateau, which also encompasses the Ke Bang and Hin Namno karsts. The limestone is not continuous and demonstrates complex interbedding with shales and sandstones. This, together with the capping of schists and apparent granites has led to a particularly distinctive topography. The caves demonstrate discrete episodic sequences of events, leaving behind various levels of fossil passages, formerly buried and now uncovered palaeokarst (karst from previous, perhaps very ancient, periods of solution); evidence of major changes in the routes of underground rivers; changes in the solutional regime; deposition and later re-solution of giant speleothems and unusual features such as sub-aerial stromatolites. The location and form of the caves suggests that they might owe much of their size and morphology to some as yet undetermined implications of the schists and granites which overlay the limestone. On the surface, there is a striking series of landscapes, ranging from deeply dissected ranges and plateaux to an immense polje. There is evidence of at least one period of hydrothermal activity in the evolution of this ancient mature karst system. The plateau is probably one of the finest and most distinctive examples of a complex karst landform in SE Asia. In summary, Phong Nha displays an impressive amount of evidence of earth’s history. It is a site of very great importance for increasing our understanding of the geologic, geomorphic and geo-chronological history of the region

Location

Phong Nha - Ke Bang National Park is located in the territories of communes ((Vietnamese): xã): Tan Trach, Thuong Trach, Phuc Trach, Xuan Trach and Son Trach of Bo Trach district and a small part of Minh Hoa district in the center of Quang Binh province, around 40 km north-west of the provincial capital city of Dong Hoi. The park is bordered by Hin Namno karst area of Khammouan Province of Laos in the west. The road distances are about 500 km south of the capital Hanoi and 260 km north of the port city of Da Nang. The geographical coordinates are 17°32′14″N, 106°9′4.5″E.

The park is situated around 30 km west of South China Sea and National Road 1A, near Ho Chi Minh Highway and 28 km west of Hanoi-Saigon Railway and is accessed by road or waterway by boat through the estuary in South China Sea upwards. There is a small airport near the park accessible by helicopter or small aircraft (Khe Giat Airbase), an airbase used by North Vietnamese Airforce during Vietnam War, notably in the Battle of Dong Hoi.

History of formation

The Phong Nha–Ke Bang karst has evolved since the PaleozoicPalaeozoic (some 400 million years ago) and so is the oldest major karst area in Asia. It has been subject to massive tectonic changes, and comprises a series of rock types that are interbedded in complex ways. Probably as many as seven different major levels of karst development have occurred as a result of tectonic uplift and changing sea levels, thus the karst landscape of PNKB is extremely complex with high geodiversity and many geomorphic features of considerable significance. Like much of Vietnam, it has been subject to extensive tectonic change, and so the limestones of Phong Nha are inter-bedded with a number of other rocks. There is also strong evidence that sulphurous solution and hydrothermal action have played an important role in shaping the broad-scale landscape and the caves, though this has not yet been properly assessed.

Geological significance

Phong Nha-Ke Bang National Park is one of the world's two largest limestone regions. In comparison with 41 other world heritage sites which have karsts, Phong Nha has dissimilar geomorphic, geologic and biotic conditions. The karsts of Phong Nha can be traced back to Palaeozoic era, 400 million years ago. This makes Phong Nha the oldest major karst in Asia. If the Hin Namno, bordering Phong Nha on the west (in Laotian territory) was to be combined with the national park in a continuous reserve, the combined reserve would be the largest surviving karst forest in South-east Asia (317,754 ha).

In general, there are two groups of landforms in the Phong Nha - Kẻ Bàng area, namely non-karstic and karstic landforms. Non-karstic landforms includes three types: The middle and low dome-block mountains developed in intrusive magmatic massifs; The middle denudation-structural mountain belts developed in terrigenous rocks of Cretaceous age; and The low block-denudational mountain belts developed in other terrigenous rocks.

Karstic landforms in this area are of typical tropical karst which are divided into two groups of forms: The karstic forms on the surface including cone and tower karst, karrens, valleys and dolines, border polje, etc; The underground karst consisting of caves.

Mounts and summits

Phong Nha - Ke Bang also contains two dozens of mountain peaks with over 1,000 metres height. Noteworthy peaks are the Peak Co Rilata with ta height of 1,128 m and the Peak Co Preu with a height of 1,213 m.

Mounts in karstic area of the park rise at typical height of above 800 m constitute a continous range along Laotian-Vietnamese borderline, of which notable summits above 1000 m are: Phu Tạo (1174m), Co Unet (1150m), Phu Canh (1095m), Phu Mun (1078m), Phu Tu En (1078m), Phu On Chinh (1068m), Phu Dung (1064m), Phu Tu Ôc (1053m), Phu Long (1015m), Phu Ôc (1015m), Phu Dong (1002m). Inserting into these summits are 800-1000 m high summits of Phu Sinh (965m), Phu Co Tri (949m), Phu On Boi (933m), Phu Tu (956m), Phu Toan (905m), Phu Phong (902m), núi Ma Ma (835m).

Cave and grottoes

Phong Nha-Ke Bang covers 300 different grottoes and caves. Phong Nha cave is assesed by BCRA as the top cave in the world due to its 4 top records: the longest underground river, the highest and longest cave, broadest and most beautiful fine sand beaches inside the caves, the most spectacular stalagmites and stalactites.According to the assessment of UNESCO, The karst formation of Phong Nha-Ke Bang National Park has evolved since the Palaeozoic (some 400 million years ago) and so is the oldest major karst area in Asia and Phong Nha displays an impressive amount of evidence of earth’s history. It is a site of very great importance for increasing our understanding of the geologic, geomorphic and geo-chronological history of the region