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.

It's a 30-day-old Echidna baby, known as a “puggle” – one of only 24 ever bred in captivity. The proud parents are Tippy and Pickle of Australia Zoo. The tiny baby, whose s*x has not yet been identified, hatched from a soft egg and will continue to develop and nurse inside Tippy's warm pouch. (Photo by Australia Zoo/Rex/Sipa Press)

A three-day-old Bengal tiger calf is cared for after being fed at the National Zoo in Masaya on August 30, 2021. A female Bengal tiger calf was born in the National Zoo of Nicaragua, the fourth of this species in risk of extinction born in captivity in the country, and is under special care due to a limited breastfeeding capacity of the mother. (Photo by Inti Ocon/AFP Photo)

A motorcyclist performs the superman stunt on a highway in Kuala Lumpur, Malaysia, September 14, 2014. Crowds of small motorbikes ridden by racers – or “Mat Rempit”, as they are known in Malaysian slang – face off in impromptu races in the Malaysian capital after dark. The decades-old culture is widely frowned upon by largely conservative Malaysians, who fear its potential to encourage gambling, drug abuse, snatch thefts and sexual promiscuity. (Photo by Olivia Harris/Reuters)

In this April 2, 2016 photo, dusty sculptures made of cast-off baby dolls sit in an open-air museum and art workshop off a trash-strewn street cutting through some of the poorest neighborhoods in Port-au-Prince, Haiti. They were created by Haitian artists called Atis Rezistans who have become celebrated in the international art world by creating sculptures out of scrapped car parts, old wood, discarded toys and even human skulls found scattered outside crumbling mausoleums. (Photo by David McFadden/AP Photo)

A toque macaque is eating flowers in the water at the pilgrimage site in Polonnaruwa, Sri Lanka, on January 13, 2024. The toque macaque (Macaca sinica), a reddish-brown-colored Old World monkey, is endemic to Sri Lanka, where it is known as the rilewa or rilawa. It is named for the whorl of hair at the crown of its head, which resembles a brimless toque cap. (Photo by Thilina Kaluthotage/NurPhoto/Rex Features/Shutterstock)

“Serengeti National Park encompasses 5,700 square miles of grassy plains and woodlands near the northern border of Tanzania, and is home to more than 3,500 lions grouped into a couple dozen prides. Photographer Nick Nichols and videographer Nathan Williamson made several extended trips to the Serengeti between July 2011 and January 2013, determined to break new visual ground in their coverage of the Serengeti Lions”. Photo: Cubs of the Simba East pride: too young to kill but old enough to crave meat. Adult females, and sometimes males, do the hunting. Zebras and wildebeests rank high as chosen prey in the rainy season. (Photo by Michael Nichols/National Geographic via The Atlantic)

Barrier tape is tied around 15-month-old Shivani's ankle to prevent her from running away, while her mother Sarta Kalara works at a construction site nearby, in Ahmedabad, India, April 19, 2016. Kalara says she has no option but to tether her daughter Shivani to a stone despite her crying, while she and her husband work for 250 rupees ($3.8) each a shift digging holes for electricity cables in the city of Ahmedabad. (Photo by Amit Dave/Reuters)