Son Doong features in British nature documentary series Planet Earth III

Narrated by Sir David Attenborough, the series is about the resilience and adaptability of nature and the remarkable animals that are changing their lives to meet the challenges of a rapidly changing world.

It will feature eight episodes in which viewers can see some of the most amazing species in their natural habitats.

Series producer Matt Brandon said the crew spent a total 1,904 days filming the series.

"The crew trek for two days through the Vietnamese jungle with 500 kilograms of equipment to reach the world's largest natural cave, Son Doong, where the team then lived for 18 days underground (longer than anyone has ever spent in the cave before)," he told the BBC.

Other locations across Asia that appear in the series include Gomantong and Sukau in Malaysia, Raja Ampat in Indonesia, the Maldives, the Gobi Desert in Mongolia, Yala National Park in Sri Lanka, Sukkur Region in Pakistan, and West Bengal in India.

In 2016, the crew of Hollywood movie "Kong, Skull Island" came to Quang Binh to film some scenes inside the cave.

The cave has achieved international fame since it opened to tourists in 2013.

Oxalis Adventure exclusively operates tours to Son Doong, with a four-day-three-night expedition costing VND69.8 million (US$3,000).

Only 1,000 visitors are allowed a year for environmental reasons, and the tours are available only between January and August.

Planet Earth, aired in 2006, won numerous western awards.

In 2016 the BBC aired a six-episode sequel, called Planet Earth II.

VNE