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)

This picture taken on September 11, 2023 shows Moon Jellyfish (with rings) and Sting Jellyfish (yellow-orange inside) among a smack of a several thousand swimming off Seglvik, in northern Norway. (Photo by Olivier Morin/AFP Photo)

A diver dressed in a Santa Claus costume swims at the Lotte World Aquarium in Seoul, South Korea, Monday, December 23, 2024. (Photo by Ahn Young-joon/AP Photo)

Neutral athletes Mayya Doroshko and Tatiana Gayday compete in the women's duet technical preliminary of artistic swimming at the World Aquatics Championships in Singapore, Friday, July 18, 2025. (Photo by Vincent Thian/AP Photo)

A toddler held by her father swims underwater during a swimming class for babies at Lane Cove pool February 16, 2007 in Sydney, Australia. (Photo by Ian Waldie/Getty Images)

In an observance of Epiphany, Russian Orthodox believers swim in an icy pond outside Nizhny Novgorod, Russia. (Photo by Olga “Zwezdochka”)

A man dressed in a Halloween costume swims along the coast of the northern Lebanese city of Batroun, on October 28, 2021. (Photo by Ibrahim Chalhoub/AFP Photo)