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)

Nigel Cox and Kevin Jay paint with light using fibre optic whips on the beach at Clacton-on-Sea in Essex, United Kingdom on July 25, 2023 with a superhero fighting theme. (Photo by Kevin Jay/Picture Exclusive)

A Brazil fan waits for the start of the group A World Cup soccer match between Brazil and Croatia, the opening game of the tournament, in the Itaquerao Stadium in Sao Paulo, Brazil, Thursday, June 12, 2014. (Photo by Felipe Dana/AP Photo)

UEFA staff member carry away the trophy from the pitch prior the UEFA Champions League semi-final football match between Leipzig and Paris Saint-Germain at the Luz stadium in Lisbon on August 18, 2020. (Photo by David Ramos/Pool via AFP Photo)

Gold medalist Shelly-Ann Fraser-Pryce of Jamaica celebrates after the Women's 100m Final during the 18th edition of the World Athletics Championships at Hayward Field in Eugene, Oregon, United States on July 17, 2022. (Photo by Aleksandra Szmigiel/Reuters)

A rainbow over the windmill in Lytham, Lancashire on May 17, 2022 at sunset after rain hit the region last night after the hottest day of the year. (Photo by Gregg Wolstenholme/Bav Media)

Carnival revelers perform during the Academicos do Baixo Augustaa carnival “bloco” parade in Sao Paulo, Brazil, Sunday, February 24, 2019. (Photo by Andre Penner/AP Photo)

A South Korean marine in action during their regular drill on Yeonpyeong Island, South Korea November 1, 2018. (Photo by Jeon Heon-Kyun/Pool via Reuters)