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)

A B-52 bomber is watched by a group of curious onlookers as it lands at RAF Fairford, February 21, 1999. The B52s arrived from the U.S.A. as part of NATO's preparations for air attacks on Yugoslavia as tensions in the Kosovo crisis increased. (Photo by Dylan Martinez/Reuters)

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

A man stands on a mountain summit as he looks over the Inntal valley in the western Austrian village of Gnadenwald, Austria on July 18, 2017. (Photo by Dominic Ebenbichler/Reuters)

Elizabeth Nicolaou, a final year student with the Royal Academy of Dance, strikes a pose on April 28, 2022 near the Cutty Sark ship in Greenwich, London ahead of International Dance Day. First celebrated in 1982, International Dance Day has taken place every year since in anniversary celebration of the birth of Jean-Georges Noverre (1727-1810), considered the creator of modern ballet. (Photo by Guy Corbishley/Alamy Live News)

Rows of blossoming peach trees line the fields of Aitona, in the province of Lleida, north eastern Spain, on March 22, 2025. Every year in March the thousands of hectares of blossoming peach trees create a sort of nature tourism with hundreds of people visiting the area to take in the colorful blossoms. (Photo by Josep Lago/AFP Photo)

A couple take photographs alongside the National Monument on Calton Hill, Edinburgh on Wednesday January 5, 2022, ahead of First Minister Nicola Sturgeon's update to the Scottish Parliament on the Covid-19 situation as the Omicron variant sweeps across the country. (Photo by Jane Barlow/PA Images via Getty Images)