Son doong cave is a cave in Phong Nha-Kẻ Bàng National Park, Bố Trạch district, Quảng Bình Province, Vietnam. Currently the biggest known cave in the world, the cave is located near the Laos-Vietnam border. Inside is a large, fast-flowing underground river.
In early August 2013, the first tourist group explored the cave on a guided tour at a cost of US$3,000 each. The group had six members from Australia, Norway, Russia and USA and spent 7 days and 6 nights for the tour. Next exploration trips will be arranged.

A picture taken with a drone shows a huge work of art created with various flowers and flowering plants in Jacobsdorf, Germany, 29 July 2024. Artist Michael Uy has transformed a piece of fallow land into an insect paradise for bees, bumblebees and butterflies. Using plants, the artist has planted and sown oversized images in the shape of a shell and a winding path of life on a large meadow in Jacobsdorf. (Photo by Hannibal Hanschke/EPA/EFE)

Portraits single nominee: Dakar fashion, by Finbarr O’Reilly. Curious residents and a street vendor selling material look on as models Diarra Ndiaye, Ndeye Fatou Mbaye and Malezi Sakho wear outfits by the Senegalese designer Adama Paris in the Medina neighbourhood of Senegal’s capital, Dakar. (Photo by Finbarr O’Reilly/World Press Photo 2019)

A Vietnamese cosplayer poses as police officer character from the game during the League of Legends (LOL) Mid-Season Invitational 2019 play-in group stage, in GG Stadium, Ho Chi Minh, Vietnam May 5, 2019. (Photo by Reuters/Kham)

Pakistani vendors carry animals in a bus for the upcoming Muslim festival Eid al-Adha in Lahore, Pakistan, Monday, August 5, 2019. Eid al-Adha, or Feast of Sacrifice, is the most important Islamic holiday and marks the willingness of the Prophet Ibrahim (Abraham to Christians and Jews) to sacrifice his son. (Photo by K.M. Chaudhry/AP Photo)

Vietnam’s Son Doong cave, the largest in the world, could hold a 40-story skyscraper inside. The pristine ecosystem has its own river and jungle. Despite its size, Son Doong wasn’t discovered until 1991. It was lost again for nearly two decades and was fully explored for the first time in 2009. (Photo by Jason Speth/HuffPost)

Two hippopotamus are fed with pumpkins at the Hanoi Zoo, in Hanoi, Vietnam, 25 October 2018. The zoo has been the home for more than 800 animals of over 90 different species, including three hippopotamus, since it was built in 1976. (Photo by Luong Thai Linh/EPA/EFE)

In this Wednesday, September 12, 2018, file photo, vendors carry banana on their heads at a fruit and vegetable market in Peshawar, Pakistan. Pakistan says it will seek a bailout loan from the International Monetary Fund to address a mounting balance of payments crisis, Finance Minister Asad Umar said Monday. (Photo by Muhammad Sajjad/AP Photo)