Hang Sơn Đoòng

Largest cave passage in the world, located in Quảng Trị, Vietnam

Sơn Đoòng Cave (Vietnamese: hang Sơn Đoòng, IPA: [haŋ˧ ɕɤn˧ ɗɔŋ˨˩]), in Phong Nha–Kẻ Bàng National Park, Quảng Trị province, Vietnam, is the world's largest natural cave. Located near the Laos–Vietnam border, Hang Sơn Đoòng has an internal, fast-flowing subterranean river and the largest cross-section of any cave, worldwide, believed to be twice that of the next-largest passage. It is the largest known cave passage in the world by volume.

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