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)

In this April 4, 2017 photo, Zoologist Martha Llanes caresses baby chimpanzee Anuma II, left, while Ada hangs on to her leg, at Llanes' apartment in Havana, Cuba. She has forgiven them every transgression. It's hard to stay angry at a baby chimpanzee when it clambers up your leg and into your arms and plants a kiss on your cheek in a plea for forgiveness. (Photo by Ramon Espinosa/AP Photo)

A Bosnian special forces soldier returns fire 06 April 1992 downtown Sarajevo as he and civilians come under fire from Serbian snipers. The Serb extremists were shooting from the roof of a hotel at a peace demonstration of some of 30,000 people as fighting between Bosnian and Serb fighters escalated in the capital of Bosnia- Hercegovina. (Photo by Mike Persson/AFP Photo)

A B-52 bomber is watched by a group of curious onlookers as it lands at RAF Fairford, February 21, 1999. The B52s arrived from the U.S.A. as part of NATO's preparations for air attacks on Yugoslavia as tensions in the Kosovo crisis increased. (Photo by Dylan Martinez/Reuters)

Castle rising in the mist on April 14, 2022. Castle Rising is a ruined medieval fortification in the village of Castle Rising, Norfolk, England. It was built soon after 1138 by William d'Aubigny II, who had risen through the ranks of the Anglo-Norman nobility to become the Earl of Arundel. (Photo by Terry Harris/The Times)

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 balloon takes part in the 43rd International Hot Air Balloon Festival in Chateau-d'Oex, Switzerland on January 24, 2023. (Photo by Denis Balibouse/Reuters)

Children walk amid a mirror installation titled “Sea of Mirrors”, featuring digital images of fish in the ocean during a preview tour the day before the show's public opening at the AquaRio aquarium in Rio de Janeiro, Brazil, Wednesday, June 14, 2023. (Photo by Silvia Izquierdo/AP Photo)