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)

Evel Knievel is shown in his rocket before his failed attempt at a highly promoted 3/4-mile leap across Snake River Canyon in Twin Falls, Idaho, on September 8, 1974. The jump failed when the parachute on his rocket malfunctioned, opening prematurely. Knievel was uninjured. (Photo by AP Photo)

A gaggle of goslings huddle together under the protective wing of a parent along the bank of the Deschutes River as a heavy downpour passes through Bend, Oregon, late Wednesday, April, 20, 2106 afternoon. (Photo by Ryan Brennecke/The Bulletin via AP Photo)

Naga Sadhus, or Hindu holy men, participate in the procession for taking a dip in the Ganges river during Shahi Snan at “Kumbh Mela”, or the Pitcher Festival, amidst the spread of the coronavirus disease (COVID-19), in Haridwar, India, April 12, 2021. (Photo by Danish Siddiqui/Reuters)

A crustacean walks on a road after flooding went back in Schuld, Germany, Friday, July 16, 2021. Two days before the Ahr river went over the banks after strong rain falls causing severals deaths and hundreds of people missing. (Photo by Michael Probst/AP Photo)

Poisoned River. Abstract Winner. A detailed photograph of a stream filled with poison. “Poisoned Beauty” is a personal project that tells the story of the natural disaster in the Apuseni Mountains in Transylvania, which was a result of chemical waste generated by copper and gold mining, but in a beautifully abstract way. (Photo by Gheorghe Popa/Drone Photography Awards 2021)

A young girl is splashed as she takes an elephant bath at Rapti river in Chitwan, Nepal, 30 October 2021. Chitwan is one of the major tourist destinations in Nepal and popular zone for wild life sightseeing in Chitwan National Park. (Photo by Narendra Shrestha/EPA/EFE)

A Nepalese woman offers prayers to the setting Sun on the bank of Bagmati River during the Chhath Puja festival in Kathmandu, Nepal, Wednesday, November 10, 2021. During Chhath, an ancient Hindu festival, rituals are performed to thank the Sun God for sustaining life on earth. (Photo by Niranjan Shrestha/AP Photo)