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)

West Bromwich Albion's Saido Berahino (front) is challenged by Manchester City's Fernandinho during their English Premier League soccer match at The Hawthorns in West Bromwich, central England December 4, 2013. (Photo by Eddie Keogh/Reuters)

Britain's Emma Raducanu attends a practice session ahead of the Australian Open tennis tournament in Melbourne on January 13, 2022. (Photo by Mike Frey/AFP Photo)

A polar bear fast asleep at London Zoo. (Photo by Fox Photos/Getty Images). 1961

A paramedic enters an ambulance vehicle as she responds to a call received by Ambulance Station No 3 of Rostov-on-Don's Emergency Care Hospital on New Year's Day in Rostov-On-Don, Russia on January 1, 2022. (Photo by Erik Romanenko/TASS)

Visitors observe the sculpture “That Girl” by U.S. artist Paul McCarthy, at the Hyperrealist Sculpture 1973-2016 exhibition in the Museum of Bellas Artes in Bilbao, northern Spain, July 27, 2016. (Photo by Vincent West/Reuters)

Swiss Alisha Lehmann, right, fights for the ball with Czech Republic's Jana Petrikova during the UEFA Women's Euro 2022 play-off 2nd leg qualification match between Switzerland and the Czech Republic at the Stockhorn Arena in Thun, Switzerland, 13 April 2021. (Photo by Alessandro Della Valle/EPA/EFE)

Inquisitive elephant seal pups venture towards a photographer on South Georgia, an uninhabited island near Antarctica early July 2022. The seals are not used to seeing humans and shuffled closer to Charlotte Rhodes rather than shying away. (Photo by Charlotte Rhodes/Media Drum Images)