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)

Gray whale feeding at the surface and showing it's baleen. (Photo by Christopher Swann/Biosphoto)

Norway's Karsten Warholm celebrates winning the men's 400m hurdles at the Diamond League in London, July 21, 2018. (Photo by Andrew Boyers/Action Images via Reuters)

Winston Leonard Spencer Churchill (1874–1965), British Statesman and Prime Minister inspecting the boys from a training ship. (Photo by Hulton Archive/Getty Images). 1912

Aidan Thomas wears a Smokey Bear t-shirt as he watches smoke from the Airport Fire rise behind Meander Lane in Trabuco Canyon, Calif., on Monday, September 9, 2024. (Photo by Jeff Gritchen/The Orange County Register via AP Photo)

A person carries a fan in Westminster, London, Britain, 12 July 2022. Britain has been issued with an amber weather warning for the weekend as experts predict that temperatures could rise to the high thirties and Sunday could be the hottest day on record for the UK. (Photo by Tolga Akmen/EPA/EFE/Rex Features/Shutterstock)

Cyril Despres of France tries to get his Peugeot out of the sand as co-pilot David Castera pushes the car during the 10th stage of the Dakar Rally 2016 near Fiambala, Argentina, January 13, 2016. (Photo by Marcos Brindicci/Reuters)

Mechanics work in the Buggy belonging to Argentina's Manuel Sisterna and Adrian Echegaray during technical verification ahead of the Dakar Rally 2015 in Buenos Aires January 1, 2015. (Photo by Enrique Marcarian/Reuters)