The period between 2001 and 2005 represents a special chapter in the journey of British cavers in Vietnam. By 2001, the team - based primarily in the village of Son Trach - had already identified the existence of two primary cave systems within Ke Bang Massif: the Phong Nha system and the Hang Vom system. The expeditions during this five-year window were characterized by deep-jungle cave exploration with basecamps set inside Hang En cave and jungle.
A team of four British cavers and one geologist had a five-day camp in Hang En on this expedition to resolve the cave undiscovered. This led to the discovery of Hang Lanh, a resurgence cave and one of the feeders to the Phong Nha System. Also Hang Doi and Hang Ca were explored in this area.
By the end of 2001, the Phong Nha system reached a total length of 44.5km, solidifying its status as the longest cave system in Vietnam.
The expedition of this year successfully surveyed and mapped a total of 4.690m.
Key Achievements
- Hang Lanh: The cave is 3,753m long. It serves as a significant upstream feeder, contributing its flow to the broader Phong Nha hydrological system.
- Hang Doi: Located downstream from the main Hang En camp, this cave consists of a large dry passage explored for a total of 453m.
- Hang Ca: Exploration of this 361m branch requires a continuous swim through cold, clear waters that are believed to originate from the distant Khe Tien sink.
The 2003 expedition focused on pushing deeper into the dense wilderness of the Ruc Ca Roong area. The mission's primary objective was to extend the upstream exploration of the Hang Vom system while systematically surveying the rugged terrain situated between the known sinks and resurgences of both major networks.
The expedition of this year successfully surveyed and mapped a total of 6.257 m.
Key Achievements
- Hang About (Hang Vom Cave System): This year recorded an exploration of 820m of Hang About, which served as a vital hydrological link within the massive Hang Vom system. The cave is characterized by its rugged and raw interior, featuring sharp limestone riverbeds and large breakdown sections that demand careful navigation. Unlike more decorative systems, its walls are stark and smooth - a testament to the powerful floodwaters that scour the passage during the monsoon season. The cave’s most striking feature is the "Jade Splinter" entrance, an elegant elliptical portal that frames the vibrant green jungle outside.
- Hang Nuoc Nut: With a grand entrance 15m wide and 30m high, the cave opened high-level fossil passages and active river canyons. The main trunk of the cave is truly monumental, with some sections widening to over 50m and adorned with colossal stalactites and intricate rimstone pools. A highlight of the system is the “Stal Magicians’ Workshop”, , a gallery of exceptional aesthetic beauty. The exploration typically follows the "Ribbit River" canyon, a deep-water passage that eventually rises from a terminal sump.
The cave has a total length of up to 2.2 kilometers and is estimated to be around 2 million years old
- Hang So Doi (Rice Bowl): Located near historic road traces, Hang So Doi is 1,124m long. Its interior features dry, gravel-floored passages that open into spacious galleries decorated with elegant flowstones and crystal-clear calcite pools.
- Hang So Dua (Chopstick Cave): is a smaller cave of 260m long. It is characterized by tight, muddy fissures and challenging crawls that lead briefly into a gentle river passage before the water retreats into a terminal sump.
In this year the team explored caves in the Vom System, Hang Klung, Kling and A Cu. In Minh Hoa District two significant river caves were explored Ma Nghi for 610m and Thuy Van for 691m. The team also visited Quang Ninh District, and found some significant caves. Hang Rao May 136m and Birthday Cave 388m are part of what is now quite an extensive river cave system. Hang Cha Rao, a resurgence cave, was explored for 2 kilometres, without a conclusion, stopping at a waterfall which was too wet to climb.
The team also started to explore areas to the West of the Chay river. Exploring Hang Nuoc Lan 965m and Hang Da Trang 270m. Near Phong Nha Village Hang Duc 1335m was explored. Also explored was Hang Me Bon Con 732m. This cave was significant, because the guide also took the team to another entrance, which turned out to be the dry entrance to Hang Vom. This entrance had been explored from the original Hang Vom entrance in 1992, and not seen since. This entrance was developed in 2010 and is now Paradise Cave, open to the general public, and is a very spectacular show cave.
The expedition of this year successfully surveyed and mapped a total of 11.5km.
Key Achievements
Hang Klung
With a length of over 1,085m, Hang Klung is an impressive cave that connects to the Rục Cà Roòng river system. The cave features a steep entrance slope that leads into a massive chamber filled with ancient stalactites and dry rimstone pools. A strong draft of air guides explorers through its giant passages, some of which measure up to 50m wide.
Hang Kling
Hang Kling is a smaller cave, measuring approximately 120m in length. It is located near a local cave settlement and serves as a short, transit-style passage through the limestone cliffs.
Hang Ma Nghi/Thuy Van
Located in the Minh Hoa District, these two river caves measure 610m and 691m respectively. They are characterized by active water passages that require swimming and wading through high-level fossil sections. The caves are quite accessible, featuring sandy floors and unique fissures that lead back out to the jungle surface.
Ma Nghi Cave and its massive stalactite formations.
Hang Cha Rao
Measuring over 2,008m, Hang Cha Rao was the longest cave explored during the 2005 expedition. This spectacular river cave is famous for its extremely long swimming sections and emerald-blue water. The journey inside involves navigating through magnificent calcite dams and challenging waterfalls, eventually ending at a vertical waterfall.
Stalactites inside Cha Rao Cave
Hang Nuoc Lan
Hang Nuoc Lan reaches a length of 965m and is famous for its monumental entrance, which is as large as a highway tunnel. The interior is truly grand, with some sections reaching 60m in width and 50m in height. It features a rugged terrain of house-sized boulders and ends at a deep, noisy pit.
Hang Me Bon Con
This 732m cave is a hidden gem located near the famous Hang Vom. It has incredibly fragile and rare formations, including "cave pearls" and unique cone-shaped mud structures that look like a miniature forest.