Son Doong is the only Vietnamese representative in the list of 10 'most incredible caves in the world' published by Canadian magazine The Travel.
"Being 200m high and 175m wide as well as 9.4km in length, this cave is estimated to fit a 40-story New York skyscraper," it said.
Tourists on an underground river inside Son Doong Cave in central Vietnam.
Son Doong in the Phong Nha-Ke Bang National Park in the central province of Quang Binh has hogged the international spotlight since it opened to tourists in 2013.
"The most fascinating elements are a thick forest mushrooming in the cave for years as well as towering stalagmites and cave pearls. It requires two days of intense jungle trekking and river crossings to reach the entrance of Son Doong Cave."
Oxalis Adventure operates the tour, with a four-day-three-night expedition to the cave costing VND69.8 million (US$3,000).
Only 1,000 visitors are allowed a year for environmental reasons, and the tour is available only between January and August.
Trekkers accompanied by a specialist go through unique underground rainforests, kayak in rivers both above and below ground and climb a 90-meter-high wall dubbed "The Great Wall of Vietnam" with ropes and ladders.
Batu Cave in Malaysia and Tham Lod Cave in Thailand are two other Southeast Asian representatives in the list.