This picture taken with an underwater camera shows Japan' s Yumi Adachi competing in the Mixed Duet technical final during the synchronised swimming competition at the 2017 FINA World Championships in Budapest, on July 17, 2017. (Photo by Bernadett Szabo/Reuters)

A diver wearing a Santa Claus costume swims with fishes in a large tank during an underwater performance for the upcoming Christmas celebration at Hakkeijima Sea Paradise in Yokohama, south of Tokyo, Japan on December 1, 2022. (Photo by Kim Kyung-Hoon/Reuters)

A new book published by the UK Natural History Museum showcases some of the most memorable underwater photographs taken over the last few decades in its annual wildlife photographer of the year competition. Here: Giant gathering by Tony Wu. “The first indication that something extraordinary was going on were the blows, huge numbers of them – the exhalations of huge numbers of whales. Entering the water, the photographer witnessed an extraordinary scene”. (Photo by Tony Wu/Unforgettable Underwater Photography/NHM)

Aquarium visitors attend a dinner party in an underwater tunnel in Tianjin, China on September 15, 2016. Tianjin Haichang Polar Ocean World opened in the city of Tianjin, southeast of Beijing, in 2010. It gives visitors a chance to see more than 150 large animals from the Arctic and Antarctic regions, including polar bears. (Photo by Feature China/Barcroft Images)

Dublin student beat depression by befriending sharks, stingrays and pigs in the Bahamas. Awesome underwater pictures show the 23-year-old diver cosying up to a range of animals including turtles, stingray and sharks. The sunny selfies were taken in the Bahamas by Stuart’s Cove dive instructor and native of the island, Amelia Klonaris – who beat depression by embracing her incredible beach paradise lifestyle. (Photo by Amelia Klonaris/Mediadrumworld)

These unique photos capture the moment a boy has his teeth picked clean by amazing underwater shrimp. These fascinating creatures spend their lives diving inside the mouths of fish to remove the parasites that lurk there. Russell Laman imitated the behaviour of the surrounding fish swarm to entice the cleaner shrimp into his mouth whilst snorkelling with his father Tim Laman in Bali, Indonesia. The 13-year-old queued with the waiting fish and then opened his mouth when the shrimps came near. (Photo by Tim Laman/Caters News)

Underwater photographer Sarah Lee uses a technique known as “duck diving” to capture these stunning photos of surfers in Hawaii. Surfers “duck dive” under the water to avoid incoming waves so they can get further out to sea. Photo: A surfer comes free from her surfboard. (Photo by Sarah Lee/Caters News)

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)