A BREATHTAKING VIDEO! Sơn Đoòng Cave (the Moutain-River Cave), is a solutional cave in Phong Nha-Kẻ Bàng National Park, Vietnam. As of 2009 it has the largest known cave passage cross-section in the world! Video: Son Doong Cave – The Moutain River Cave (Hang Sơn Đoòng)
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