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 row of abandoned oil tanks is filled with creepers on the riverside of Liyun River in Huai 'an, East China's Jiangsu Province, May 9, 2023. (Photo credit should read CFOTO/Future Publishing via Getty Images)

Maddie Stanton (L) and River compete in Helen Woodward Animal Center's 18th Annual Surf Dog Surf-A-Thon at Del Mar Dog Beach on September 10, 2023 in Del Mar, California. (Photo by Daniel Knighton/Getty Images)

Tourists fly in hot air balloons over the west bank of the Nile River on January 9, 2025 in Luxor, Egypt. Luxor, which contains the historical city of Thebes, capital of ancient Egypt's pharaohs at the height of their power, is full of pharaonic monuments and other antiquities. (Photo by Ahmad Hasaballah/Getty Images)

“The finless porpoise (Neophocaena phocaenoides) is one of six porpoise species. In the waters around Japan, at the northern end of its range, it is known as the sunameri. A freshwater population found in the Yangtze River in China is known locally as the jiangzhu or «river pig»”. – Wikipedia

Photo: A newly born Yangtze finless porpoise (top) swims with his mother at the Hydrobiology Institute of the Chinese Academy of Sciences on June 3, 2007 in Wuhan of Hubei Province, China. (Photo by China Photos/Getty Images)

Swimmers climb out of a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. According to organisers, about 700 swimmers across China took part in the event on the official launch day of the Harbin Ice and Snow Sculpture Festival. (Photo by Kim Kyung-Hoon/Reuters)

A Rohingya Muslim from Myanmar (R), who tried to cross the Naf river into Bangladesh to escape sectarian violence, cries near his family in a Bangladeshi Coast guard station in Teknaf on June 19, 2012, before being sent back to Myanmar. (Photo by Munir Uz Zaman/AFP Photo)

Brazilian farmer Jander Santos de Souza (R) checks his corn plantation which is inundated with floodwaters from the Solimoes River, in the rural municipality of Manacapuru, Amazonas state May 5, 2015. According to the association of farmers in the community, about 70 percent of the agricultural production was lost due to the flooding. (Photo by Bruno Kelly/Reuters)