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 Mercedes-Benz 300 SL “Gullwing” Coupe is displayed during an exhibition of vintage and classic cars by Bonhams auction house at the Grand Palais during the Retromobile week in Paris, France, February 8, 2017. (Photo by Benoit Tessier/Reuters)

Somali women sing as they celebrate the election of President Mohamed Abdullahi Mohamed in the streets of Somalia's capital Mogadishu, February 9, 2017. This election is important because it may establish a pattern of peaceful change of government as well as continue to grow Somalia’s institutions especially for a country that has not heard a stable government for more than two decades. (Photo by Feisal Omar/Reuters)

Actress Anya Taylor-Joy attends the British Vogue And Tiffany & Co. Celebrate Fashion And Film Party 2024 at Annabel's on February 19, 2024 in London, England. (Photo by Richard Young/Rex Features/Shutterstock)

“Cockayne syndrome (also called Weber-Cockayne syndrome, or Neill-Dingwall Syndrome) is a rare autosomal recessive congenital disorder characterized by growth failure, impaired development of the nervous system, abnormal sensitivity to sunlight (photosensitivity), and premature aging. Hearing loss and eye abnormalities (pigmentary retinopathy) are other common features, but problems with any or all of the internal organs are possible. It is associated with a group of disorders called leukodystrophies. The underlying disorder is a defect in a DNA repair mechanism. It is named after English physician Edward Alfred Cockayne (1880–1956)”. – Wikipedia

Photo: Mother of 12-year-old Chinese girl Sun Yangyang suffering from Cockayne syndrome, tends her at the First Affiliated Hospital of Jilin University on November 11, 2006 in Changchun of Jilin Province, China. The disease results in the senile appearance of Yangyang and also causes eyesight, hearing weakness and other problems. Doctors failed to cure the girl... (Photo by China Photos/Getty Images)

An undated handout photo obtained on May 14, 2022, from Khartoum's Marshall Nature Reserve for exotic birds, shows a visitor posing for pictures with some of the protected birds in the capital Khartoum. Tucked away east of Sudan's capital Khartoum, a sanctuary of lush green vegetation has been a haven for dozens of exotic birds from far and wide. (Photo by Khartoum Marshall Nature Reserve/AFP Photo)

Hundreds of people from a range of NGOs and campaign groups protest to demand the immediate restoration of nature at DEFRA – Department for Environment Food & Rural Affairs on September 28, 2023 in London, England. The 2023 State of Nature Report revealed that approximately one in six species in Great Britain, including turtle doves and hazel dormice, are at risk of extinction, citing climate change, intensive farming, and pollution as major threats, with a 19% average decline in monitored plant and animal populations since 1970. (Photo by Guy Smallman/Getty Images)

Russian army soldiers, dressed in WWII era uniforms, march along the Red Square during a general rehearsal for the Victory Day military parade which will take place at Moscow's Red Square on May 9 to celebrate 70 years after the victory in WWII, in Moscow, Russia, Thursday, May 7, 2015. (Photo by Ivan Sekretarev/AP Photo)