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.

Slovenian photographer Peter Gedei started caving 25 years ago and has carried a camera with him on every trip getting stunning pictures from his travels, capturing the ice formations, tight chambers and beautiful halls. Photo: The Ice Cave in Postojna, Slovenia. (Photo by Peter Gedei/Caters News)

A motorcycle modified to run on rails is seen inside a tunnel connected to the Altiplano Federal Penitentiary and used by drug lord Joaquin “El Chapo” Guzman to escape, in Almoloya de Juarez, on the outskirts of Mexico City, July 15, 2015. U.S. law enforcement officials met with agents of the Mexican attorney general's office this week to share information related to the escape from prison of Guzman and coordinate efforts to apprehend him, a Mexican government official said on Wednesday. (Photo by Edgard Garrido/Reuters)

Dutch artists Lernert and Sander cut raw food into 98 perfect 2.5 x 2.5 x 2.5 cm cubes, creating a tantalizing geometric display. This viral photo was commissioned by Dutch newspaper de Volkskrant for their their food-themed documentary photography special.

“Adventurers have gone deep underground to discover previously unexplored caves in these pictures. The awe-inspiring snaps show the cavers dwarfed by the huge series natural rock chambers in the Leye – Fengshan Geopark, China. Belgian photographer Francois-Xavier De Ruydts, 33, captured the team of explorers as they trekked through the deep wonderground in January 2014”. – Caters News. Here: Caving expedition in Fengshan, China, Guangxi province. (Photo by Francois-Xavier De Ruydts/Caters News)