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)

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

A kid casts his hand's shadow as kids play with light in “L'art dans la nature, Dali universe” an open air light show at Parc de la Villette in Paris, France on November 19, 2023. (Photo by Gonzalo Fuentes/Reuters)

Waxwings in Balham south London on December 31, 2023. There has been a huge influx of this erruptive species this year. This probably due to severe storms and a shortage of food in their native Scandinavia in the Autumn. (Photo by Jack Hill/The Times)

A man walks along a corridor at a hotel in Singapore on February 7, 2024. (Photo by Edgar Su/Reuters)

Bjorn, aged 5, smiles as he poses with a Owl butterfly during an event to launch the Sensational Butterflies exhibition at the Natural History Museum in London, Britain March 23, 2016. The exhibition opens to the public on March 24 and runs until September 11. (Photo by Dylan Martinez/Reuters)