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 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)

A model walks off stage in the backstage area during Frankie's Bikinis show at Mercedes Benz Swim Fashion Week in Miami, July 18, 2014. (Photo by Carlo Allegri/Reuters)

Team GB synchronised swimmers Kate Shortman and Izzy Thorpe took on an underwater fashion shoot in June 2021 before they represent Britain in the artistic swimming competition at the Tokyo Olympics next month. (Photo by Bluebella/Cavendish Press)

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)

Divers swim beside millions of silverside fish at Devil's Grotto, Cayman Islands. Swimming in unison, millions of silverside fish dwarf the divers. The fish create waves of silver light as they move around the grottos that lie beneath the surface of the Caribbean Sea. These amazing photographs were captured by Belgian photographer Ellen Cuylaerts, 44, on a diving trip to the Devil's Grotto, Cayman Islands. (Photo by Ellen Cuylaerts/This is Guavo Media)