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)

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)

People watch an eruption of the South East volcano of Etna is seen from the village of Nicolosi, Italy February 10, 2022. (Photo by Antonio Parrinello/Reuters)

People visit the artwork titled Seven Magic Mountains by artist Ugo Rondinone, Wednesday, May 11, 2016, near Jean, Nev. The artwork was recently completed in the desert south of Las Vegas. (Photo by John Locher/AP Photo)

Tropical acrobatics by Adrià López Baucells in Manaus, Brazil. An unidentified South American marsupial, although the characteristic black markings on its face indicate it may be a mouse opossum. These small creatures are nocturnal and feed on bugs, fruit and bird eggs. (Photo by Adrià López Baucells/2019 Royal Society of Biology Photography Competition)

Actress Maddie Ziegler holds her bag as she poses during People's “Ones To Watch” event celebrating Hollywood's rising and brightest stars in West Hollywood, California September 16, 2015. (Photo by Kevork Djansezian/Reuters)

A mountain jerboa, which is taken under protection after his mother dies, is seen at Yuzuncu Yil University Wild Animal Protection and Rehabilitation Center in Van, Turkiye on June 24, 2022. (Photo by Mesut Varol/Anadolu Agency via Getty Images)