- Hang Son Đoòng
- 200/150/6.5 dimension(s)
- Vietnam ()
Hang Son Đoòng (the name means "Mountain River Cave") is the world's largest single cave passage, based on its overall dimensions. It is around 200 metres (655 feet) high, 150 metres (490 feet) wide and has a length of at least 6.5 kilometres (4 miles). Son Đoòng is located in Phong Nha-Ke Bàng National Park, Bo Trach District, Quang Bình Province, Vietnam.
The cave might be even larger than originally thought, as it had not been completely surveyed as of February 2012. It was originally discovered in 1991 by a local farmer named Ho Khanh. In April 2009, he directed a team of British cavers to the cave, and they made a survey of it, as far as possible.