A Ukrainian servicewoman walks at a position, as Russia's attack on Ukraine continues, in Luhansk Region, Ukraine on April 26, 2022. (Photo by Serhii Nuzhnenko/Reuters)

The first female attack helicopter pilot of Türkiye's Atak helicopter, Deputy Commissioner Özge Karabulut, undisclosed location, Türkiye, January 6, 2022. (Photo by Anadolu Agency via Getty Images)

A girl holds her brother in her arm as black smoke rises after an oil well set on fire in the center of al-Kayyara town to the south of Daesh terror organization-held Mosul in Iraq on October 25, 2016. The oil well in the center of al-Kayyara town, which was set alight by retreating Daesh militants in advance of the Iraqi army's takeover of the town on August 24, 2016 has still not entirely been put out. The raw petrol which is still alight is creating black clouds above the city. The residents and wildlife beneath this polluting smoke cloud may find their health at risk. The effects of the fire in the town center on unprotected civilians' health can easily be seen on the hands and faces of children playing on the street. (Photo by dris Okuducu/Anadolu Agency/Getty Images)

Soldiers patrol in Petion Ville, the neighborhood where the late Haitian President Jovenel Moise lived in Port-au-Prince, Haiti, Wednesday, July 7, 2021. Moïse was assassinated in an attack on his private residence early Wednesday, and first lady Martine Moïse was shot in the overnight attack and hospitalized, according to a statement from the country’s interim prime minister. (Photo by Joseph Odelyn/AP Photo)

Sneha Mindani, 14, one of the survivors of the April 2019 Easter Sunday bomb attack, wipes her tears as her father delivers a speech during a protest to demand justice for this attack, on the third anniversary of the event, near the Presidential Secretariat, amid the country's economic crisis, in Colombo, Sri Lanka, April 17, 2022. (Photo by Navesh Chitrakar/Reuters)

A bank employee exits the bank through a window broken by attackers, in Beirut, Lebanon, Wednesday, September 14, 2022. (Photo by Hussein Malla/AP Photo)

Palestinians inspect the damage caused by Israeli attacks in Gaza City on January 9, 2025. (Photo by APAImages/Rex Features/Shutterstock)

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.