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.

These photographs appear to show a spectacular underwater world making it ideal for scuba divers – in central Europe. Twelve metres of water covers trees, footpaths, benches and bridges that are usually accessible throughout the year. Visitors to the Green Lake in Tragoess, Austria, that is normally only one metre deep, can leisurely stroll around the picturesque lagoon. Photo: A diver crossing a bridge in the flood water. (Photo by Solnet/The Grosby Group)

Lieke Martens of Netherlands is tackled by Andi Sullivan of USA during the FIFA Women's World Cup Australia & New Zealand 2023 Group E match between USA and Netherlands at Wellington Regional Stadium on July 27, 2023 in Wellington / Te Whanganui-a-Tara, New Zealand. (Photo by Amanda Perobelli/Reuters)

England's Rachel Daly celebrates scoring their side's sixth goal of the game with team-mates during the FIFA Women's World Cup 2023, Group D match at the Hindmarsh Stadium, Adelaide, Australia. Picture date: Tuesday August 1, 2023. (Photo by Hannah Mckay/Reuters)

Denmark's forward #10 Pernille Harder celebrates scoring her team's first goal during the Australia and New Zealand 2023 Women's World Cup Group D football match between Haiti and Denmark at Perth Rectangular Stadium in Perth on August 1, 2023. (Photo by Luisa Gonzalez/Reuters)

Men who are part of a neighbourhood vigilante group hold a hammer and machetes while posing for a photograph after suspected gang leader Makandal was killed and set on fire, amid an escalation in gang violence, in Port-au-Prince, Haiti on March 20, 2024. (Photo by Ralph Tedy Erol/Reuters)

This jaw-dropping footage shows one brave diver getting up close and personal with a group of sharks as he feeds them a long-awaited meal. Ken Kiefer from Houston, Texas captured his friend, Jake, reaching right into the mouth of a hammerhead. (Photo by Ken Kiefer/Caters News Agency)

This handout picture released by the Israeli army on May 31, 2024 shows Israeli soldiers during operations in the Gaza Strip amid the ongoing conflict between Israel and the Palestinian militant group Hamas. (Photo by Israeli Army/AFP Photo)