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)

Students from Cambridge University in England make their way home along Trinity Lane after celebrating the end of the academic year at a May Ball in Trinity College on June 18, 2019. (Photo by Joe Giddens/PA Images via Getty Images)

Swimmers in the Sky Pool, a transparent swimming pool suspended 35 meters above ground between two apartment buildings, during hot weather in Nine Elms, central London on Monday, August 12, 2024. (Photo by James Manning/PA Images via Getty Images)

The burning Polaris of Jose Antonio Blangino of Argentina sits in the sand dunes during stage one of the 2012 Dakar Rally from Mar Del Plata to Santa Rosa de la Pampa on January 1, 2012 in Santa Rosa de la Pampa, Argentina. (Photo by Bryn Lennon/Getty Images)

An adorable baby owl has proved to be a real heart-breaker thanks to its heart-shaped head. Although Griffin the Lesser Sooty Owl might look like a feather duster, the tiny eight-week old chick will soon be ready to fly. And the heart outline that surrounds his giant eyes and beak means he is set to be the star of the bird show at Taronga Zoo, Sydney. (Photo by Caters News Agency)

Jiff with Playboy Playmates arrives at the Playboy Super Bowl XLIX Party on Friday, January 30, 2015 in Scottsdale, Ariz. (Photo by Omar Vega/Invision/AP Photo)

German shoemaker Georg Wessels (R) presents shoes to Win Zaw Oo, who according to his medical team, at 2.3 metres (7.5 ft), is Myanmar's tallest man, in Yangon March 26, 2014. (Photo by Reuters/Minzayar)

A full size working replica of the pink limousine used by Parker to chauffeur Lady Penelope in Gerry Anderson's television series “Thunderbirds”, unveiled at Woburn Abbey. United Kingdom, 27th May 1968. (Photo by Jim Gray/Keystone/Getty Images)