People swim underwater at Clovelly Beach on December 14, 2023 in Sydney, Australia. A severe heat wave hit Sydney over the weekend, a precursor of hot and dry conditions expected for the rest of the summer which will also bring heightened bushfire risk. The mercury rose to alarming levels again on Thursday. (Photo by Jenny Evans/Getty Images)

Zoi Karangelou of Greece compete in the Women's Solo Technical final on day one of World Aquatics Artistic Swimming World Cup Super Final 2025 at Xi'an Olympic Sports Centre on June 13, 2025 in Xi An, China. (Photo by Lintao Zhang/Getty Images)

A man wearing a water-filled helmet in which a goldfish swims performs an act titled “Aquaman” during the Night Festival 2016 in Singapore, 20 August 2016. The ninth edition of the festival will run from 19 to 27 August and features installations and performances by a range of international and local artists. (Photo by Wallace Woon/EPA)

A winter swimmer, wearing a Santa Claus hat to celebrate the upcoming Christmas, reacts as he plays on a frozen lake at a park in Shenyang, Liaoning province, December 22, 2014. The characters on the hat read: “Shenyang Winter Swimming”. (Photo by Reuters/Stringer)

Playful seals. The pair of playful seals swim around each other. Two passionate seals were captured on camera in a tender embrace by underwater photographer Robert Bailey, 50, near the Farne Islands off the Northumberland coast, UK. (Photo by Robert Bailey/Medavia)

A young child reaches out to a Gentoo penguin as it swims in its enclosure at Pairi Daiza Park in Cambron-Casteau, Belgium, Monday, July 5, 2021. Pairi Daiza, one of the biggest zoos in Europe, has recently added ten Gentoo penguins to their animal population. (Photo by Virginia Mayo/AP Photo)

A Snowboarder participates in a waterslide contest, which consists of gliding over a water pool embedded in snow, during the closing event of the ski resort of Nendaz, southwestern Switzerland, Monday, April 21, 2014. (Photo by Maxime Schmid/AP Photo/Keystone)

Festival-goers take a bath in a mud pool during the 20th Boryeong Mud Festival on Daecheon beach in Boryeong City, some 190 kilometers west of Seoul, South Korea, 22 July 2017. Tourists flock to the area to experience the beneficial properties of the Boryeong mud, as well as for a variety of entertainment events. The festival runs from 21 until 30 July. (Photo by Jeon Heon-Kyun/EPA/EFE)