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)

Britain's Catherine, Duchess of Cambridge, shelters from the rain under an umbrella as she arrives at the London School of Economics to mark the launch of The Royal Foundation Centre for Early Childhood, where she took part in a roundtable discussion on the Centre's inaugural report, “Big Change Starts Small” which was released today, in London on June 18, 2021. (Photo by Richard Pohle/Pool via AFP Photo)

An endangered desert bighorn lamb leaps in play at a park where bighorns are tempted to leave the safety of their native habitat to eat grass and drink water in the summertime on August 9, 2023 near Indio, California. (Photo by David McNew/Getty Images)

Samba dancers arrive to perform ahead of the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Sunday, August 14, 2016. (Photo by Jae C. Hong/AP Photo)

Elio Angulo (bottom C) lies inside a cardboard coffin next to Alejandro Blanchard as they introduce their product to potential customers at a mortuary in Valencia, in the state of Carabobo, Venezuela August 25, 2016. When Venezuelan entrepreneurs Alejandro Blanchard and Elio Angulo decided to create cardboard coffins, they were looking for an ecological selling point to compete against classic wood and brass caskets. Three years on, with the oil-rich country mired in deep economic crisis, their “bio-coffins” are becoming a viable option because of high prices for wooden coffins and shortages of brass ones. (Photo by Marco Bello/Reuters)

Netherland's Kitty van Male is hit in the face by Argentina's Agustina Habif during the women's quarterfinal field hockey game, August 15, 2016. (Photo by Carl de Souza/AFP Photo)

Dutch cyclist Fabio Jakobsen's bicycle (behind, L) flies through the air as he collides with compatriot Dylan Groenewegen (on the ground, L) during the opening stage of the Tour of Poland race in Katowice, southern Poland on August 5, 2020. The Dutch rider was fighting for his life on Wednesday after he was thrown into and over a barrier at 80km/h in a sickening conclusion to the opening stage of the Tour of Poland. (Photo by Szymon Gruchalski/Forum/AFP Photo)

A model has her hair sprayed backstage at the Ukrainian Fashion Week in Kyiv, Ukraine on August 31, 2020. (Photo by Gleb Garanich/Reuters)