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)

Participants of the “Lady in red“ procession, marking the day of the Summer Solstice, walk on a promenade of the Yenisei River in Krasnoyarsk, Russia on June 22, 2019. (Photo by Ilya Naymushin/Reuters)

Waxwings in Balham south London on December 31, 2023. There has been a huge influx of this erruptive species this year. This probably due to severe storms and a shortage of food in their native Scandinavia in the Autumn. (Photo by Jack Hill/The Times)

Event entertainer Holly Egan poses with a guitar using an angle grinder as Kevin Jay and Nigel Cox spin burning steel wool, sending sparks flying under the A13 in Essex, UK on April 4, 2024. (Photo by Kevin Jay/Picture Exclusive)

An areal view of the lake in the form of a heart in Rodgau, near Frankfurt, Germany, Friday, May 24, 2024. (Photo by Michael Probst/AP Photo)

A view of northern lights over the skies of Sodankyla, Lapland, Finland, on October 7, 2024. (Photo by Alexander Kuznetsov/Courtesy of All About Lapland/Handout via Reuters)

A bird stands near people waiting on South Padre Island to watch the SpaceX Starship rocket launch from Starbase, Texas, on May 27, 2025. SpaceX mission control lost contact with the upper stage of Starship as it leaked fuel, spun out of control, and made an uncontrolled reentry after flying halfway around the world, likely disintegrating over the Indian Ocean, officials said. (Photo by Sergio Flores/AFP Photo)