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)

A model wears a creation by “Como un pez en el agua” (Like a fish in the water) for the Spring/Summer 2017-2018 fashion show as part of 080 Barcelona fashion week in Barcelona, Spain, Thursday, June 29, 2017. (Photo by Manu Fernandez/AP Photo)

A young Afghan vendor waits for customers to buy sheep's heads at a roadside stall at the busy market in Kabul on November 29, 2015. (Photo by Wakil Kohsar/AFP Photo)

A member of the USA Knights team is seen wearing a face-like helmet shield during the International Medieval Combat championships at the castle of Belmonte, May 4, 2014, in Belmonte, Spain. The steel armor the knights wear can cost up to $10,000 and weigh 80 pounds. (Photo by Juan Naharro Gimenez/Getty Images)

In this November 9, 2014 photo, a man sits on the rope holding his bull by the neck as he waits to enter it in a bull fight in Leogane, Haiti. The obscure Haitian practice of fighting bulls is brutal like a cock or dog fight, but on a larger scale. A casual pastime for some rural men, it is serious business for others looking to pay their children's school fees or even buy a car. (Photo by Dieu Nalio Chery/AP Photo)

Aerial view of Taxodium Distichum in full blossom at a maze area of a wetland park on January 6, 2023 in Xiamen, Fujian Province of China. (Photo by Wu Wei/VCG via Getty Images)

A soldier fires a rocket gun as Ukrainian soldiers in the Donetsk region, where the country's most intense clashes occur, attend intensive combat training by using both domestic and foreign weapons amid Russia-Ukraine war in Donetsk, Ukraine on May 08, 2023. Infantry is always prepared in a conflict where heavy weaponry like aircraft, helicopters, tanks and other heavy armored vehicles, artillery systems, and mortars are widely deployed on frontline. Combat readiness and experience training of the 57th Brigade of the Ukrainian army continues in Donetsk. (Photo by Muhammed Enes Yildirim/Anadolu Agency via Getty Images)

Ukrainian soldiers fire the D-30 artillery to Russian positions in the direction of Klishchiivka as the Russia-Ukraine war continues in Donetsk Oblast, Ukraine on August 12, 2023. (Photo by Diego Herrera Carcedo/Anadolu Agency via Getty Images)