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)

These stunning pictures show a normally vicious tiger calmly swimming in a pool of algae, on Jule 9, 2014. The powerful cat takes a refreshing break by taking a dip in the bright green algae. But it looks like this big cat is scared of getting his head wet as he strains to keep it above the water. After splashing around for a bit the tiger gets out and tries to air-dry with specks of the vegetation dripping off his fur. The striking pictures were taken at Copenhagen zoo by snapper Soren Lundgren Neilson. (Photo by Soren Nielsen/Caters News)

A cyclist rides in al-Qudra desert in the Gulf emirate of Dubai, on June 8, 2020. (Photo by Giuseppe Cacace/AFP Photo)

The DFDS King of seaways enters the Mouth of the Tyne on the North East coast in Rough sea on Wednesday, January 18, 2023. (Photo by Owen Humphreys/PA Images via Getty Images)

Migrant children play with leaves during Christmas Eve at a shelter, as they travel with their parents as part of a caravan with humanitarian visas to transit throughout the country, in Monterrey, Mexico on December 24, 2021. (Photo by Daniel Becerril/Reuters)

China's Zheng Si Wei, right, and Huang ya Qiong play against Thailand's R. Makkasasithorn and J. Sudjaipraparat during their mixed doubles match at the Badminton Asia Championships 2022 at Muntinlupa, Philippines on Tuesday, April 26, 2022. (Photo by Aaron Favila/AP Photo)

Suzanna Shahbazian of Canada competes in the Individual Exercises Final during Pan American Gymnastics Championships Rio de Janeiro 2022 at Carioca Arena 1 on July 09, 2022 in Rio de Janeiro, Brazil. (Photo by Buda Mendes/Getty Images)

Wendy Adriaens, owner of animal rescue farm “De Passiehoeve” and nicknamed the Ostrich Whisperer, poses for a photo with three-year-old male ostrich Flodder, in Kalmthout, Belgium, 25 July 2022. (Photo by Stephanie Lecocq/EPA/EFE/Rex Features/Shutterstock)