A section of underground river inside Son Doong cave

The cave ranked third after the Inca Trail in Peru and Burning Man festival in Nevada, the US.

“The incredible depths of the world’s largest cave lure travelers who want a true adventure. But the arduous journey into this subterranean site makes booking a trek essential,” said Lonely Planet.

Currently, the sole tour operator that takes travelers inside, Oxalis Adventure Tours, says on its website that less than 300 spaces remain for 2019 tours.

Other spots that made the list are the Under restaurant in Norway which open its doors in April 2019 and Solar Eclipse in South America which will be visible over parts of Chile and Argentina on July 2nd, 2019.

Deputy Head of the Quang Binh Department of Tourism, Dang Dong Ha said this year, a program of exploring a new underwater way with about 600m in length will be carried out inside the cave. The trip is expected to find a way from the existing cave system with a nearby cave (Thung cave) with the participation of four leading diving experts who have joined the rescue campaign of the football team in Thailand in July 2018.

If the program is successful, the Son Doong cave system will have some records to continue holding its position of the world’s largest cave.

In 2019, the Department will coordinate with big news agencies around the world to film reality television programs in Son Doong cave and Phong Nha - Ke Bang National Park./.