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 walks on a slackline during the 7th edition of the European “Marmotte Highline Project” (MHP) festival in Lans-en-Vercors, near Grenoble, eastern France, on July 4, 2019. The event, during which the participants will be able to evolve on the various highlines located in the Regional Natural Park of Vercors, takes place until July 7, 2019. (Photo by Philippe Desmazes/AFP Photo)

New Forest ponies graze as the sun rises over Godshill in the New Forest, Hants on September 18, 2022, on the day before the Queen's state funeral tomorrow. (Photo by Claire Sheppard/Solent News & Photo Agency)

Ghanaian fans take a selfie prior to a Group G football match between Germany and Ghana at the Castelao Stadium in Fortaleza during the 2014 FIFA World Cup on June 21, 2014. (Photo by Patrik Stollarz/AFP Photo)

Gymnast Simone Biles performs a flip after throwing out the ceremonial first pitch prior to Game Two of the 2019 World Series between the Houston Astros and the Washington Nationals at Minute Maid Park on October 23, 2019 in Houston, Texas. (Photo by Tim Warner/Getty Images)

A red fox sits in front of a Eurofighter Typhoon combat jet on the grounds of the 2014 ILA Berlin Air Show, in Selchow near Schoenefeld, Germany, Thursday, May 15, 2014. The International Aviation and Aerospace Exhibition ILA will take place from May 20 until May 25, 2014. (Photo by Patrick Pleul/AP Photo/DPA)

This photo taken on February 10, 2025 shows a captured green iguana being held by hunters after it was brought down by a slingshot in Pingtung. Taiwan's iguana population has exploded since the spikey-backed giant lizards were introduced from Central and South America more than 20 years ago as exotic pets. Many escaped or were dumped by their owners and have bred rapidly in the warm climate of southern Taiwan, invading neighbourhoods and ravaging farmers' crops. (Photo by I-Hwa Cheng/AFP Photo)

A lovely sunrise in at the beachfront of Playa de Muro, Alcudia on the island of Mallorca, Majorca, Spain on May 16, 2022. As a road cyclist walks his road bike along a wooden jetty heading out into the calm waters. (Photo by Phil Wilkinson/Alamy Live News)