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)

In this September 19, 2019 file photo, an aircraft passes the rising sun during take off at the international airport in Frankfurt, Germany. Germany’s top court has ruled that the government has to set clear goals for reducing greenhouse gas emissions after 2030, arguing that current legislation doesn’t go far enough in curbing climate change. (Photo by Michael Probst/AP Photo/File)

Icelandic horses walk in their paddock at a stud farm in Wehrheim near Frankfurt, Germany, as the sun rises Tuesday, June 1, 2021. (Photo by Michael Probst/AP Photo)

Members of Brighton Swimming Club brave the early morning temperature to take a dip in the sea east of the pier on January 5, 2022. The club, founded in 1860, is the oldest in England. (Photo by Simon Dack/Alamy Live News)

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

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)

Racegoers brave the conditions during 2022 Melbourne Cup Day at Flemington Racecourse on November 1, 2022 in Melbourne, Australia. (Photo by Martin Keep/Getty Images for VRC)

A person holds an umbrella against strong wind and rain as he walks on a street Friday, June 2, 2023, in Kawasaki near Tokyo, as a tropical storm was approaching. (Photo by Eugene Hoshiko/AP Photo)