Phong Nha–Kẻ Bàng (, ) is a national park and UNESCO World Heritage Site in the Bố Trạch and Minh Hóa Commune of central Quảng Trị Province in the North Central Coast region of Vietnam, about 500 km south of Hanoi. The park borders the Hin Namno National Park in Khammouane Province, Laos to the west and 42 km east of the East Sea from its borderline point. Phong Nha–Kẻ Bàng National Park is in a limestone zone of 2,000 km2 in Vietnamese territory and borders another limestone zone of 2,000 km2 of Hin Namno in Laotian territory. The core zone of this national park covers 857.54 km2 and a buffer zone of 1,954 km2.
The park was created to protect one of the world's two largest karst regions with 300 caves and grottoes and also protects the ecosystem of limestone forest of the Annamite Range region in North Central Coast of Vietnam.
Phong Nha–Kẻ Bàng is noted for its cave and grotto systems as it is composed of 300 caves and grottos. A 2009 survey brought the total discovered length of the cave system to about 126 km, with many areas still not well explored. Sơn Đoòng Cave, which was discovered in the 2009 survey by British and Vietnamese explorers, is considered the largest cave in the world. Even before this discovery, Phong Nha held several world cave records, including the longest river as well as the largest combined caverns and passageways.
The park derives its name from Phong Nha Cave, containing many rock formations, and Kẻ Bàng forest. The plateau on which the park rests is one of the finest and most distinctive examples of a complex karst landform in Southeast Asia. This national park was listed in UNESCO's World Heritage Sites in 2003 for its geological values as defined in its criteria viii. In April 2009, the world's largest cave was re-discovered by a team of British cave explorers of the British Caving Association led by a local farmer named Ho Khanh.
History of exploration Champa inscriptions carved on steles and Buddhist altars in the cave dating from the 9th century demonstrate that people had inhabited the cave long before the area was annexed by Vietnam in the Nam tiến or southward expansion. The cave was first mentioned in literature in 1550, appearing in Dương Văn An's works. This cave was depicted in 9 urns in the Citadel of the Nguyễn dynasty in Huế. In 1824, The cave was conferred the title "Diệu ứng chi thần" () by King Minh Mạng. It was also conferred by Nguyen kings as "Thần Hiển Linh" ().
In the late 19th century, Léopold Michel Cadière, a French Roman Catholic priest, conducted an expedition to explore Phong Nha cave, where he discovered Champa scripts. He proclaimed Phong Nha cave "The number one cave of Indochina". In July 1924, an English expeditionist (surnamed Barton) stated that Phong Nha cave is second to none of famous caves of Padirac (France), Cuevas del Drach (Spain). In 1935, a local inhabitant accidentally discovered a beautiful cave 1 km from the mouth of Phong Nha cave, at an elevation of . It was called Tien Son cave (lit.: Fairy-tale cave), or Dry cave because its inside landscape is similar to fairy-tales and it has no underground river.
In 1937, the Bureau of Tourism of French Resident Superior (in Huế) issued a brochure to introduce tourism in Quảng Bình and Phong Nha Cave was included in this introduction. This tour site is ranked second in French Indochina. Before 1990, several explorations were conducted by Vietnamese and foreign groups but the mystery of this area still remained. From 1990 on, there marked a turning point in discovering activities, from exploration to research, thus full documents for submission to UNESCO for World Natural Heritage nomination were made available.
IN 1990, for the first time, Hanoi University accepted the cooperation proposal of the British Cave Research Association. They combined efforts in exploring and researching caves and grottoes in the area comprehensively. The first exploration was conducted in 1990 by a group from the British Cave Research Association and Faculty for Geology and Geography of Hanoi University, led by Howard Limbert. They completed research of a large part of Vom Cave. In 1992, the second exploration was conducted by a group of 12 British scientists, six professors from Hanoi University. This time, this group completed their exploration of 7,729 m of Phong Nha Cave and 13,690 m of Vom Cave and adjacent caves and grottos. In 1994, a third exploration was carried out by a group of 11 British scientists and five Vietnamese professors of Hanoi University. In 1999 scientists from the Vietnam-Russia Tropical Centre also conducted zoological and botanical surveys in the Kẻ Bàng area. Based on the results of these three explorations, more information about the caves and grottoes made available to the Vietnamese and local government for the protection, planning, and tourism development of this park.
In 2005, scientists from the British Cave Research Association discovered a new cave and named it Paradise Cave (động Thiên Đường). The newly discovered cave was acclaimed by the British scientists as "the largest and the most beautiful cave in Phong Nha–Kẻ Bàng area".
On June 1, 2006, the Ministry of Culture and Information of Vietnam issued a stamp collection of depicting various landscapes found in Phong Nha–Kẻ Bàng.
In April 2009, a group of cave explorers from British Caving Association conducted survey in this park and adjacent areas. The biggest chamber of Sơn Đoòng is more than five (5) kilometers in length, 200 meters high and 150 meters wide. With these dimensions, Sơn Đoòng overtakes Deer Cave in Malaysia to take the title of the world's largest cave. At the same time they found new caves and grottoes in the park and adjacent area.Britons claim to find world's largest cave, Daily Telegraph, 1 May 2009 In this survey, the cave British explorers discovered 20 new caves with total length of 56 km, including world's largest cave, Sơn Đoòng.
Geography
Location
Phong Nha–Kẻ Bàng National Park is in the territories of communes (Vietnamese: xã): Tan Trach, Thuong Trach, Phuc Trach, Xuan Trach and Son Trach of Bố Trạch District and a small part of Minh Hóa District in the center of Quảng Bình Province, around 40 km north-west of the provincial capital city of Đồng Hới. The park is bordered by the Hin Namno karst area of Khammouane Province of Laos in the west. Road distances are about 500 km south of the capital Hanoi and 260 km north of the port city of Đà Nẵng. The geographical coordinates are .
The park is around 30 km west of the South China Sea and National Route 1, near Hồ Chí Minh Highway and 28 km west of the Hanoi–Saigon Railway, and is accessible by road or waterway through an estuary in the South China Sea. There is a small airport near the park accessible by helicopter or small aircraft (Khe Gat Airbase), an airbase used by the North Vietnamese Air Force during the Vietnam War, notably in the Battle of Đồng Hới.
Park layout Before becoming a national park, this area had been a nature reserve. The Phong Nha Nature Reserve with an area of 50 km2 was officially declared by the Vietnamese government on 9 August 1986 and was extended to 411.32 km2 by 1991. On 12 December 2001, the Vietnamese Prime Minister by Decision 189/2001 189/2001/QĐ-TTG turning then a nature reserve into a national park. The purpose of this protected area is to protect forest resources, biodiversity within the boundary of this national park and to preserve scientific values of fauna and flora in Bắc Trung Bộ region, especially rare species native to this region. The park covers a total area of 857.54 km2 which are divided into three zones, a "strictly protected zone" (648.94 km2), an "ecological recovery zone" (174.49 km2), and an "administrative service zone" (34.11 km2).
Climate Like North Central Coast in general, and Quảng Bình Province in particular, the climate in Phong Nha–Kẻ Bàng national park is tropically hot and humid. The annual mean temperature is , with a maximum of in the summer and a minimum of in the winter. The hottest months in this region fall from June to August, with an average temperature of , and the coldest months from December to February with an average temperature of . Annual rainfall is about . 88% of the rainfall falls during the monsoon, from July to December, however, there is more than 160 rainy days per year, and some rain still falls throughout the dry season. Mean annual relative humidity is 84%.
Geology
History of formation The Phong Nha–Kẻ Bàng karst has evolved since the Paleozoic (some 400 million years ago), making it the oldest major karst area in Asia. It has been subject to massive tectonic changes, and comprises a multitude of rock types that are interbedded in complex ways. 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. 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. The Phong Nha–Kẻ Bàng area today is the result of five stages of Earth's crust development and movement: Late Ordovician – Early Silurian Stage (about 450 Ma) Middle-late Devonian Stage (about 340 Ma) Carboniferous-Permian (about 300 Ma) Mesozoic Orogenic stage Cenozoic stage.
Geological significance Phong Nha–Kẻ Bàng 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 southeastern 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.
In comparison with three other national parks listed in UNESCO's World Heritage Sites in Southeast Asia, namely Gunung Mulu National Park in Malaysia, Puerto Princesa Subterranean River National Park in Palawan of the Philippines and Lorentz National Park in West Irian of Indonesia and some other karst regions in Thailand, China, Papua New Guinea, karst in Phong Nha–Kẻ Bàng is older, has more complicated geological structure; diverse and complex underground rivers.
Mounts and summits