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)

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)

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)

«Underwater». Laurie Simmons discovered this silicone sеx doll in a shop while on holiday in Japan and was immediately interested in the type of generic beauty their looks could add to her work. She went on to create the Love Doll series, in which she places silicone sеx dolls in positions that explore a woman’s interior life. (Photo by Laurie Simmons/Salon 94/The Guardian)

Photographer Mark Tipple captured the underwater pictures with his friend Mike as the surfer. But the rough waves of the coast of the Cook Islands slammed Mike into the sea bed during the shoot, causing him to slice his skin open and badly bruise his body. Photo: Mike diving beneath a shallow wave. (Photo by Mark Tipple/Caters News Agency)

If you’ve had the unique privilege of witnessing bioluminescent plankton while diving at night, you know firsthand how beautiful the underwater light show can be. For those of us who haven’t experienced it, this unique phenomenon. So what makes this beautiful show possible? In a recent post at online scuba site AquaViews they share some insight we thought you all would find interesting.

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)