A woman takes a selfie with “RoboThespian” at Robots, a major new exhibition at Science Museum in London, England on February 7, 2017. Exhibition showcases 500-year history of robots, with over 100 robots and the largest collection of humanoid robots ever displayed. (Photo by Tolga Akmen/Anadolu Agency/Getty Images)

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)

Visitors walk past sculptures on display as part of the Sculpture by the Sea exhibition in Sydney on October 29, 2019. Sculpture by the Sea is the world's largest annual, free-to-the-public, outdoor sculpture exhibition. (Photo by Peter Parks/AFP Photo)

A boy looks at a six-metre tall luminescent puppet, operated by ten performers, during a preview of Vivid Sydney, promoted as the world's largest festival of light, music and ideas, in Sydney, Australia on May 23, 2018. “Vivid” is a major outdoor cultural event featuring light installations and projections with the annual event this year running from May 25 to June 16, 2018. (Photo by David Gray/Reuters)

A leg of a “diablito” frog (Oophaga sylvatica) is photographed in a laboratory at a laboratory in the zoo of Cali, Colombia, on July 19, 2019. Colombia is the second country with the largest number of amphibians in the world after Brazil. More than 40% of amphibian species worldwide are in danger of extinction. (Photo by Luis Robayo/AFP Photo)

A pod of white pelicans, one of the largest birds in Canada and the US, are seen on the shore of the Chapala lagoon in Cojumatlan de Regules, Mexico, on January 28, 2022. White pelicans travel thousands of kilometers migrating from the cold temperatures of North America. (Photo by Ulises Ruiz/AFP Photo)

Performers ride on a train before the 40th annual Coney Island Mermaid Parade in the Brooklyn borough of New York, New York, USA, 18 June 2022. The annual event is one of the largest art parades in the country. (Photo by Yuki Iwamura/EPA/EFE)

People dressed as mermaids and mermen take part in the group swim during the MerMagic Convention at the Freedom Aquatic & Fitness Center in Manassas, Virginia on March 4, 2023. The event bills itself as the “World's Largest Mermaid Convention”. (Photo by Joseph Prezioso/AFP Photo)