Recognised by the National Speleological Society (NSS) of the United States, Kong Collapse has earned its place as the deepest sinkhole in Viet Nam and ranks among the deepest on the planet.

Lam Giang
Nestled deep within the enchanting Phong Nha-Ke Bang cave system in Quang Binh Province lies Kong Collapse, the deepest sinkhole in Viet Nam. This breathtaking natural wonder not only beckons avid explorers but also captivates those with a passion for the untamed beauty of the wild.
Kong Collapse is situated in Son Trach Commune, Bo Trach District, approximately 50km northwest of Dong Hoi City. Its discovery dates back to 1997, when a British cave expert stumbled upon it during an annual expedition to the remarkable Phong Nha-Ke Bang. At that time, accessing the sinkhole required an adventurous swim through Dai A Cave, also known as Tiger Cave. Due to its isolated nature, it was initially dubbed a 'closed sinkhole,' leaving cave enthusiasts pondering its mysteries on the map.

Fast forward over two decades, and the quest to uncover Kong's secrets took a thrilling turn. Le Luu Dung, CEO of Jungle Boss, a leading cave exploration company in Quang Binh, utilised a flycam to unveil an eye-catching glimpse of this colossal sinkhole. As the camera soared to its maximum height, it revealed a striking resemblance to the famous King Kong – a character immortalised in the blockbuster film Kong: Skull Island, which was filmed in the very same province.
Fueled by curiosity, Dung and his team embarked on an ambitious journey to explore the enigmatic cave. Their expedition required a grueling six-hour trek, including a swim through the darkened depths of Tiger Cave. Following the flycam's guidance, the team forged a path through the dense forest, navigating steep slopes without any prior human footprints, only the tracks left by mountain goats to guide them.
“The journey to Kong was as challenging as a trek to heaven,” Dung recalled. “The path was littered with sharp, cat-ear-shaped rocks, and the steep inclines left one side teetering on the edge of a cliff while the other dropped into an abyss. But once we reached Kong, the beauty of the sinkhole took my breath away. I couldn't believe I was standing in such a colossal natural formation.”
Experts consider Kong Collapse a remarkable gem within the limestone mountain system of Phong Nha-Ke Bang. This unique cave, shaped by nature over millions of years, boasts extraordinary features unlike any other. With vertical heights akin to giant skylights and minimal slopes, the cave's allure is undeniable.
Measurements of the Kong sinkhole revealed an astonishing depth of 450m, along with three distinct access points: swimming through Dai A Cave, descending via rope from the sinkhole's mouth or navigating a challenging forest trail. This makes reaching Kong Collapse one of the most thrilling cave adventure tours in Viet Nam, filled with rigorous challenges, including trekking through dense forests, swimming in pitch-black caves and exploring three interconnected caverns. And what is the highlight? A heart-pounding rope swing that drops 100m straight down into the sinkhole.
Upon entering Kong, visitors feel as though they've stepped into another realm. Sunlight streaming through the crater illuminates the enchanting space, where stalactites and stalagmites – formed over aeons – create mesmerising and otherworldly shapes. Every angle offers a new perspective, and each step unveils fresh wonders.
Kong Collapse is not just visually stunning; it's also home to a rich ecosystem. Rare flora and fauna thrive in this isolated environment, with many species evolving into unique endemics that are found nowhere else on the earth.
Nguyen Minh Tuan, a visitor from Ca Mau City, shared his experience: “The interior of the sinkhole is vast and complex, demanding both climbing skills and cave knowledge. Safety is paramount, and teamwork is essential. The challenges only heighten the thrill of the adventure.”
“I believe that anyone with a love for exploration should visit Kong sinkhole at least once. However, preparation is key – both physically and with the right safety gear. The majesty and raw beauty of this place will leave every visitor in awe,” Tuan added.
Recognised by the National Speleological Society (NSS) of the United States, Kong Collapse has earned its place as the deepest sinkhole in Viet Nam and ranks among the deepest on the planet.
Today, Kong Collapse has opened its doors to tourism, bolstered by expert guidance and the support of skilled porters. The cost for this thrilling experience ranges from VND15 million (US$612) to VND35 million ($1,430) per person for a three- to five-day exploration. However, only those who pass a medical examination and a safety skills test can embark on this unforgettable journey.
With its breathtaking beauty, Kong Collapse stands as a testament to Viet Nam's natural wonders, inviting all who seek adventure to uncover its secrets./.