A member of a winter swimming club wears flippers during the celebration of Maslenitsa, also known as Pancake Week, a pagan holiday, marking the end of the winter, in Novosibirsk, Russia. (Photo by Alexandr Kryazhev/Sputnik/Profimedia)

Australia’s Hannah Fredericks competes in the women’s 200m backstroke heats during the Australian Swimming Trials at the Brisbane Aquatic Centre on June 13, 2024. (Photo by David Gray/AFP Photo)

This aerial view shows youths swimming to cool off in the waters of Iraq's Euphrates river during a heatwave, in the district of al-Hindiyah east of Karbala on June 7, 2024. (Photo by Karar Jabbar/AFP Photo)

A person dressed as Santa Claus jumps into the sea during the Copa Nadal (Christmas Cup) swimming race in Barcelona, Spain on December 25, 2024. (Photo by Bruna Casas/Reuters)

Visitors crowd an artificial wave swimming pool at a tourist resort to escape the summer heat in Daying county of Suining, Sichuan province, China, July 11, 2015. (Photo by Reuters/Stringer)

A child looks at a polar bear swimming under a water in its enclosure on a hot summer day at Prague Zoo, Czech Republic, July 30, 2015. (Photo by David W. Cerny/Reuters)

A woman looks at a swimmer getting herself warm after the annual Christmas winter swimming competition in the Vltava river in Prague December 26, 2014. (Photo by David W. Cerny/Reuters)

A baby hippo swims under the water in its enclosure at Prague Zoo, Czech Republic, February 24, 2016. The baby was born on January 28, and is yet to be named. (Photo by David W. Cerny/Reuters)