Where is the largest cave?

Son Doong Cave, in Phong Nha-Ke Bang National Park in central Vietnam, holds the title of largest known cave passage on Earth by volume. Its main chamber is over five kilometres long, up to 200 metres high, and 150 metres wide — spacious enough to fit a 40-storey skyscraper. The cave is so vast it has its own localised weather, clouds, a jungle, and a flowing river inside. Only discovered by scientists in 2009, it was carved over millions of years by an underground river.