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)

Musician Jerome Gamble plays guitar to accompany the recorded music as it is played to the city below on September 01, 2020 in Bristol, England. Created by Bristol-based artist Luke Jerram and composer Dan Jones, “Sky Orchestra – A Moment in Time” was first performed at the Bristol International Balloon Fiesta in 2003. (Photo by Finnbarr Webster/Getty Images)

Members of the Texas Dancin' Divas take part in the Juneteenth Parade in Galveston, Texas, U.S., June 19, 2021. The United States marked Juneteenth for the first time as a federal holiday commemorating the end of the legal enslavement of Black Americans. (Photo by Adrees Latif/Reuters)

“The Dragon and The Hopper”. Eyrean earless dragon (Tympanocryptis tetraporophora) standing tall on a very hot rock in western Queensland. For a short time it was joined by a hopper, who jumped off before becoming lunch. (Photo by Harrison Warne/Nature Conservancy Australia 2021 Photo Contest)

Dancer Maithili Vijayakumar performs on the occasion of the launch of 2021 Diwali celebrations, at St. Andrew Square in Edinburgh, Scotland, Tuesday, November 16, 2021. The multi-cultural celebration will take place for the first time in two years in the center of Edinburgh on Sunday, Nov. 21. (Photo by Andrew Milligan/PA Wire via AP Photo)

A boy fires blanks from a Kalashnikov rifle, during Maslenitsa celebrations, or Shrovetide, to say farewell to winter in Minsk, Belarus, Sunday, March 1, 2020. Maslenitsa is a traditional Russian and Belarusian holiday marking the end of winter that dates back to pagan times. (Photo by Sergei Grits/AP Photo)

In this September 17, 2010 file photo a little brown bat is photographed in La Crosse Wis. Researchers for the first time found that little brown bats appear to be showing resistance to white-nose syndrome, which has killed millions of bats across North America. (Photo by Peter Thomson/La Crosse Tribune via AP Photo)

A general view shows the wreckage of armed trucks on the streets of Budapest at the time of the uprising against the Soviet-supported Hungarian communist regime in 1956. The picture was taken in the period between October 23 and November 4, 1956. (Photo by Laszlo Almasi/Reuters)