A UNESCO World Heritage seascape of 1,600 karst limestone islands and islets rising vertically from the Gulf of Tonkin, riddled with caves and home to floating fishing villages.
Ha Long means Descending Dragon in Vietnamese. The legend says a dragon flew over this bay and its tail carved the limestone towers from the seafloor, then the sea rose to fill the spaces between. The geological explanation is only marginally less dramatic.
The limestone that forms these islands is 500 million years old. Over the course of geological time, it was dissolved by rain and tropical weather into the karst landscape that covers much of Southeast Asia — vertical faces, underground caves, and tower formations. When sea levels rose after the last ice age, the valleys between the karst towers flooded, leaving only the peaks above water. What remains is 1,600 islands of varying sizes, the smallest barely large enough to stand on, the largest several kilometres across and home to cave systems the size of cathedrals.
The caves are remarkable even by comparison to the seascape above. Hang Sung Sot — Surprise Cave — runs 10,000 square metres through the interior of one island. Hang Dau Go — the Cave of Wooden Stakes — holds medieval weapons used in naval battles against Kublai Khan''s Mongol fleet in the 13th century, sunk in the rivers to impale enemy hulls.
Floating villages occupy the bay''s sheltered waters — communities of several hundred people who live, fish, and raise children on platforms anchored between the islands. The bay provides everything they need. They have never left.