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)

An Indian soldier from the international peace keeping force (IPKF) instructs young Sri Lankan recruits in shooting, part of the training given to the citizen's volunteer force in the North-Eastern Sri Lankan city of Batticaloa, September 28, 1989. (Photo by Barbara Walton/AP Photo)

A wolf looks into the camera at the 30 km (19 miles) exclusion zone around the Chernobyl nuclear reactor in the abandoned village of Orevichi, Belarus, March 2, 2016. What happens to the environment when humans disappear? Thirty years after the Chernobyl nuclear disaster, booming populations of wolf, elk and other wildlife in the vast contaminated zone in Belarus and Ukraine provide a clue. (Photo by Vasily Fedosenko/Reuters)

Sunrise over Haleakala Crater, Haleakala National Park, Maui, Hawaii on April 26th, 2011. (Photo by Robert Bush/Alamy Stock Photo)

Anne Leanzo, of Virginia, plays Ash from the Evil Dead movie and her daughter Gina, 15, plays Lilith from the Borderlands video game during Comic-Con 2017 in San Diego, California, July 22, 2017. (Photo by Bill Wechter/AFP Photo)

Bahamas' Shaunae Miller-Uibo celebrates winning the women's 200 meters final at the Diamond League Birmingham Grand Prix in Birmingham, Britain on August 18, 2019. (Photo by Jason Cairnduff/Action Images via Reuters)

Hailey Bieber attends Alexander Wang & Bvlgari Celebrate A.W. BVLGARI'S 712 Fifth Avenue on September 07, 2019 in New York City. (Photo by Paul Morigi/Getty Images)

Alien-themed decorations are seen at the Alien Research Center in Hiko, September 19, 2019. Scores of UFO enthusiasts converged on rural Nevada for a pilgrimage of sorts to the U.S. installation known as Area 51, long rumored to house government secrets about alien life, as law enforcement officials beefed up security around the military base. (Photo by Jim Urquhart/Reuters)