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)

Francisca Gomez stands at an entrance to her home, a cave where she has been living for the past 50 years, in the mountains on the outskirts of Chusmuy, Honduras April 21, 2015. The 75-year old widow receives help from neighbors and friends and she makes a little money by selling wood she collects, according to a local newspaper. (Photo by Jorge Cabrera/Reuters)

Artists preform on a pool suspended above the audience during the Fuerza Bruta dress rehearsal on February 1, 2012 in Tel Aviv, Israel. (Photo by Uriel Sinai/Getty Images)

English singer-songwriter Dua Lipa (R) holds onto a friend in a pool in the last decade of August 2022. (Photo by dualipa/Instagram)

“Danger in the mud” – a crocodile at Mana Pools National Park, Zimbabwe. The grand prize winner. (Photo by Jens Cullmann/World Nature Photography Awards 2022)

People jump into a swimming pool seeking relief from the summer heat, in Sanaa, Yemen on August 7, 2025. (Photo by Khaled Abdullah/Reuters)

The sunrise over the beach huts at Hamworthy Park in Poole, Dorset, United Kingdom on April 28, 2022. (Photo by Rachel Baker/Bournemouth News)

A dog jumps into the pool during the Flying Dogs competition in Kamnik, Slovenia, September 10, 2016. (Photo by Srdjan Zivulovic/Reuters)