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)

Visitors observe the sculpture “That Girl” by U.S. artist Paul McCarthy, at the Hyperrealist Sculpture 1973-2016 exhibition in the Museum of Bellas Artes in Bilbao, northern Spain, July 27, 2016. (Photo by Vincent West/Reuters)

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)

Icelandic horses walk in their paddock at a stud farm in Wehrheim near Frankfurt, Germany, as the sun rises Tuesday, June 1, 2021. (Photo by Michael Probst/AP Photo)

“The Dragon and The Hopper”. Eyrean earless dragon (Tympanocryptis tetraporophora) standing tall on a very hot rock in western Queensland. For a short time it was joined by a hopper, who jumped off before becoming lunch. (Photo by Harrison Warne/Nature Conservancy Australia 2021 Photo Contest)

Palestinians watch a man performs acrobatics on the beach of Gaza City, Friday, June 4, 2021. (Photo by Khalil Hamra/AP Photo)

An adult periodical cicada, in the process of shedding its nymphal skin, is visible on Saturday, May 11, 2024, in Cincinnati. There are two large compound eyes, which are used to visually perceive the world around them, and three small, jewel-like, simple eyes called ocelli at center. (Photo by Carolyn Kaster/AP Photo)

A person looks on as lava and plumes of smoke rise from a crater of Mount Etna, Europe's most active volcano, Italy on July 15, 2024. (Photo by Giuseppe Di Stefano/Etna Walk via Reuters)