While scientists have surveyed 44.5 kilometres of passages, tourists are only allowed to explore the first 1500 metres.

The climate at Phong Nha Cave is cool and pleasant, sometimes with heavy rain.

The stalagmites that used to stand at the cave's entrance apparently inspired its name: Phong Nha means "Wind and Teeth".

Phong Nha is famous for its rock formations that bear intriguing names such as the ‘Lion’, ‘Unicorn’, ‘Kneeling elephant’ and ‘the Buddha’.

After flowing about 19 km underground, the Son river emerges from the mouth of this cave, draining a huge area of the limestone mountains around Phong Nha.