Vietnam’s Son Doong cave, the largest in the world, could hold a 40-story skyscraper inside. The pristine ecosystem has its own river and jungle. Despite its size, Son Doong wasn’t discovered until 1991. It was lost again for nearly two decades and was fully explored for the first time in 2009. (Photo by Jason Speth/HuffPost)

'The Dutch charity organization Mensen in Nood (people in need) hits the streets with a remarkable campaign. People in need are posing with the typical attributes of consumer culture. The price of a designer handbag (€32) is compared with the price of a whole week of food (€4), The price a pint of beer (€4.50) with the price of 50 liter clean water (€1.50). The pictures were taken by Swedish fashion photographer Carl Stolz.' - Occupy Design UK

An indigenous woman participates in a parade called "International Indigenous Beauty" during the first World Games for Indigenous Peoples in Palmas, Brazil, October 24, 2015. Billed as the indigenous Olympics, the games are expected to attract nearly 2,000 athletes from dozens of Brazilian ethnicities, as well as from such far-flung nations as Ethiopia and New Zealand. (Photo by Ueslei Marcelino/Reuters)

Queen Elizabeth II (as Princess Elizabeth) writing at her desk in Windsor Castle, Berkshire. (Photo by Lisa Sheridan/Studio Lisa/Getty Images). 30th May 1944

An American Marine readies to land on Guadalcanal during the five-month struggle for the island between late 1942 and early 1943. Three thousand miles south of Tokyo, Guadalcanal was a major shipping point for military supplies. The Allied victory there in February, 1943, marked a major turning point in the war after a string of Japanese victories in the Pacific. (Photo by Joe Scherschel/Time & Life Pictures)

View of an American marine as he lies in a foxhole and whistles at a husky, one of the scouting dogs used during the landing on Guam, August 1944. (Photo by W. Eugene Smith/Time & Life Pictures/Getty Images)

In this handout provided by Maritime New Zealand, MV Rena is seen in two pieces after overnight bad weather pounded the vessel, on January 8, 2012 in Tauranga, New Zealand. (Photo by Maritime New Zealand via Getty Images)