Hang Én, Underground cave system in Quảng Bình Province, Vietnam.
An underground passage stretches 1,600 meters (5,250 feet) through limestone formations, creating multiple large chambers with heights reaching 120 meters (390 feet), traversed by an underground river and sand beaches.
British cavers first mapped the system in 1994 during an expedition through Phong Nha-Ke Bang National Park, documenting geological structures and connections to neighboring caves.
The name references the swiftlets that nest along the rock walls, birds revered in Vietnamese folklore for their speed and ability to navigate darkness.
Access requires a four-hour jungle trek from the nearest road endpoint, with licensed operators offering two-day expeditions that include camping gear and safety equipment, plus overnight stays inside.
Natural light enters through three large collapse openings, allowing tropical vegetation to grow inside, including trees over 30 meters (100 feet) tall that have taken root and flourish.
The community of curious travelers
AroundUs brings together thousands of curated places, local tips, and hidden gems, enriched daily by 60,000 contributors worldwide.
