Nestled deep in the lush forests of Vietnam near the Laos border, the Son Doong Cave holds the title of the largest natural cave in the world. The cave, which measures over nine kilometers in length with a volume of 38.5 million cubic meters, is so massive it could fit multiple 40-storey skyscrapers standing upright, or even an entire New York City block, including its towering buildings.
It was discovered in 1990 and first fully explored in 2009. What sets this cave apart, beyond its immense size, is the stunning world hidden within its depths. Inside, explorers have found colossal stalactites reaching up to 80 meters high, verdant rainforests thriving in collapsed sections of the cave where sunlight filters through, and even an underground river that has yet to be fully explored.
These unique features make Son Doong not just the largest, but one of the most extraordinary caves on Earth. Son Doong, which translates to "cave of the mountain river", is part of the Phong Nha-Ke Bang National Park, a UNESCO World Heritage site . This natural treasure is thought to be between two and five million years old, with its massive chambers and unique formations carved by water over millennia.
For nearly two decades, Son Doong remained largely a mystery, with its entrance first discovered by Vietnamese logger Ho Khanh in 1990. Khanh stumbled upon the cave by accident while searching for timber, but he didn't realize the magnitude of his find. It wasn't until 2009, after years of searchin.