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)

Members of the Turkana community work unblocking an irrigation canal to provide water to their sorghum crops in an arid dry area in Nanyee, near Lodwar, Turkana County, Kenya, on October 1, 2019. Turkana is a vast, dry area in the north-west of Kenya that is on the frontline of climate change. With regular searing temperatures the Turkana people are suffering from recurring and prolonged droughts. (Photo by Luis Tato/AFP Photo)

Artists wearing Japanese traditional clown masks march during the First Konpira Festival at Kotohiragu shrine in Tokyo Wednesday, January 10, 2018. The shrine is dedicated to sailors and seafaring. (Photo by Eugene Hoshiko/AP Photo)

A red squirrel sniffs out nuts inside Christmas stockings as part of the festive celebrations and enrichment programme at Wildwood Escot Park in Ottery St Mary, Devon, United Kingdom on December 17, 2020. (Photo by Ben Birchall/PA Images via Getty Images)

An alligator is pictured stuck in the mud of the dry Pilcomayo river, which is facing its worst drought in almost two decades, on the border between Paraguay and Argentina, in Boqueron, July 3, 2016. (Photo by Jorge Adorno/Reuters)

A koala named Lisa from Pappinbarra recovers from burns at The Port Macquarie Koala Hospital on November 29, 2019 in Port Macquarie, Australia. Volunteers from the Koala Hospital have been working alongside National Parks and Wildlife Service crews searching for koalas following weeks of devastating bushfires across New South Wales and Queensland. Koalas rescued from fire grounds have been brought back to the hospital for treatment. An estimated million hectares of land has been burned by bushfire across Australia following catastrophic fire conditions in recent weeks, killing an estimated 1000 koalas along with other wildlife. (Photo by Nathan Edwards/Getty Images)

More than 700 underwater images were submitted for the 2012 Annual Underwater Photography Contest, hosted by the University of Miami's Rosenstiel School of Marine & Atmospheric Science. This year, for the first time, the University of Miami set up a “Fan Favorite” category for its underwater photo competition. Internet users could vote for their favorite among five pictures. Todd Aki's photo of a jellyfish took the prize, snaring 599 of the 1,221 votes cast. (Photo by Todd Aki)

A man rides a horse while others swim on the beach of Gaza City, Friday, August 3, 2018. (Photo by Khalil Hamra/AP Photo)