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)

A swimmer stops short of a red algae bloom at Sydney's Clovelly Beach on November 27, 2012, which closed some beaches for swimming including Bondi Beach for a period of time. While the red algae, known as Noctiluca scintillans or sea sparkle, has no toxic effects, people are still advised to avoid swimming in areas with discoloured water because the algae, which can be high in ammonia, can cause skin irritation. (Photo by William West/AFP Photo)

Heads of love dolls are seen on the shelf on March 9, 2017 in Tokyo, Japan. Japan's oldest and largest “love doll” maker Orient Industry, has been producing silicone love dolls since 1977, and has seen there is a trend for intimate relationships with silicone dolls in Japan. (Photo by Taro Karibe/Getty Images)

Chunhun (R), the leader of Japan's North Korea fan club called sengun-joshi, or military-first girls, and other members practice a Moranbong Band dance in Tokyo, Japan on November 2, 2017. (Photo by Toru Hanai/Reuters)

Yuna Hiraiwa of Team Japan falls from the uneven bars during Women's Podium Training ahead of the Tokyo 2020 Olympic Games at Ariake Gymnastics Centre on July 22, 2021 in Tokyo, Japan. (Photo by Athit Perawongmetha/Reuters)

Cheerleaders from the “All Japan Cheer Organization” perform in protective masks due to COVID-19, to cheer people up in front of Shimbashi Station, one day before the start of the Tokyo 2020 Olympics in Tokyo, Japan on July 22, 2021. (Photo by Androniki Christodoulou/Reuters)

A wild water monitor (Varanus salvator) is seen swimming between colorful popcorn snacks at a Lumphini public park in Bangkok, Thailand on March 27, 2022. (Photo by Matt Hunt/Neato/Rex Features/Shutterstock)

Members of the Coney Island Polar Bear Club warm up before swimming at the beach at Coney Island in New York, December 15, 2013. (Photo by Eric Thayer/Reuters)