A US senior official and 10 ambassadors will join an expedition to Son Doong, the world's largest cave in central Vietnam, this May, local authorities confirmed on Tuesday.
Tom Malinowski, US Assistant Secretary of State for Democracy, Human Rights and Labor, and ten ambassadors from countries such as Argentina, Australia, Italy and Sweden will start the week-long adventure on May 11.
UNESCO Vietnam said the expedition will play a key role in promoting the cave.
The diplomats will be trained and assisted by leading cave explorers from Oxalis Adventure Tours, the only operator licensed to bring tourists to the cave in Quang Binh Province. The diplomats will pay for the trip themselves.
Son Doong is nothing short of a new found treasure for the province, giving it an impressive 90 percent increase in tourism revenues last year.
The cave, whose name means Mountain River, stretches for around five kilometers with at least 150 individual grottoes and shimmering rivers running through them. There is also a dense subterranean jungle that keeps growing inside the cave.
Local man Ho Khanh discovered it in 1991, and in 2009 he helped British cave experts explore it.
The cave has been praised as one of the most surreal places on earth. US magazine Smithsonian even named it the greatest place to see in the 21st century.
Son Doong was first opened to tourists on a trial basis in August 2013. Oxalis is charging tourists US$3,000 each for a one-week tour.
The tour is opened for only 500 tourists each year and tickets for this year have sold out.
Quang Binh has recently opened more caves in and around the nature reserve to tourists, including Tu Lan, Tien, Va and Nuoc Nut, all of which have amazed tourists with their captivating limestone structures and primeval sight.