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 man poses for a picture in front of Christmas lights decoration at the Francisco Morazan square in San Salvador, El Salvador, December 22, 2020. (Photo by Jose Cabezas/Reuters)

Ohio State drum major performs during the NCAA football game between the Ohio State Buckeyes and Notre Dame Fighting Irish at Ohio Stadium in Columbus on September 3, 2022. (Photo by Adam Cairns/USA TODAY Sports)

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)

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

Fog hangs over the east of the capital on a frosty Sunday morning on January 12, 2025 in London, UK. (Photo by David Levene/The Guardian)

Members of a cheerleading team warm- up during the Russian Cheerleading Championship of students in Moscow on November 20, 2016. (Photo by Natalia Kolesnikova/AFP Photo)