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.

People enjoy a bath in hot kvass, a traditional fermented beverage made from rye bread, during the sauna marathon near Otepaa, Estonia, February 6, 2016. Participants have to track down and visit the given saunas in the Otepaa area as fast as possible. (Photo by Ints Kalnins/Reuters)

These stunning images document the everyday lives of the men, women and children of the Mentawai tribe. The Mentawai people, a native population in Indonesia, are famous for their decorative tattoos and for living a semi-nomadic life on the Mentawai Islands in West Sumatra. Shot by professional photographer Mohammed Saleh Bin Dollah, the series captures a glimpse of life on the island as the Mentawai men smoke and hunt for food and the children play in the river. Here: A young boy helps a woman to prepare food taken on July 19, 2014 on the Mentawai Islands, Indonesia. (Photo by Muhamad Saleh Dollah/Barcroft Media)

An Iranian Shiite Muslim prays in Laylat al-Qadr, or the night of destiny, during holy fasting month of Ramadan after midnight, in central Tehran, Iran, early Sunday, June 18, 2017. Laylat al-Qadr is the night when Muslims believe the Quran was first revealed to prophet Muhammad. Worshipers gather in religious ceremonies to pray, ask forgiveness and make wishes on one of the most important nights of the Islamic calendar. Shiite Muslims, the vast majority of Iranians, believe the night happens either on 19th, 21st or 23rd of the holy month of Ramadan. (Photo by Ebrahim Noroozi/AP Photo)

Indian groom Prakash Sing (R) and bride Durga Prasad (C) perform marriage rituals at the Lord Shiva temple during the Maha Shivratri festival, in Kolkata, eastern India, 01 March 2022. Maha Shivaratri is celebrated with great devotion and religious fervor by Hindus, in honor of Lord Shiva with ritual bathing of Shivalingams and prayers. Unmarried women observe fast from dawn to dusk and pray to Lord Shiva to give them a good spouse. According to one of the most popular legends, Shivaratri is the wedding day of Lord Shiva and Parvati. (Photo by Piyal Adhikary/EPA/EFE)

People wait in beds during the The World's Biggest Breakfast in Bed Guinness World Record Attempt at Martin Place on March 2, 2012 in Sydney, Australia. 289 Australians join forces to create history as Martin Place is transformed into a giant bedroom. All participants was enjoy a substantial breakfast served in bed by celebrity chef “Fast” Ed Halmagyi and a free goodie bag valued at over $100. (Photo by Ryan Pierse/Getty Images)

Hindu women worship the Sun god Surya in the polluted waters of the river Yamuna during the Hindu religious festival of Chatt Puja in New Delhi October 30, 2014. Hindu women fast for the whole day for the betterment of their family and the society during the festival. (Photo by Ahmad Masood/Reuters)

People, carry food and water, past a tractor stuck in mud, stones and debris that were piled in a flood in the mountain village of Sipkovica, just above the town of Tetovo, in northwestern Macedonia, on Tuesday, August 4, 2015. A small number of people including children have died in floods that erupted after an hour of heavy torrential rains and strong winds that hit Tetovo and northwestern region of Macedonia late on Monday. (Photo by Zoran Andonov/AP Photo)