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)

Residents watch the forest burn in Portezuelo, Chile, Sunday, January 29, 2017. Chilean President Michelle Bachelet has announced that the country will continue with its various measures to deal with wild fires, one of the biggest natural disasters in the country for decades, according to a government report released on Sunday. (Photo by Esteban Felix/AP Photo)

A five-week-old orphaned Southern Sea Otter pup rests on a rubber mat after arriving at the Shedd Aquarium's Abbott Oceanarium in Chicago, Illinois October 28, 2014 in this handout photo provided to Reuters on November 5, 2014. The stranded pup was found on September 30 on Coastways Beach in California and was rescued the next day to be brought back to health at the Monterey Bay Aquarium. Southern sea otters were listed as “threatened” under the U.S. Endangered Species Act in 1977. (Photo by Brenna Hernandez/Reuters/Shedd Aquarium)

Women in Kimono holding an umbrella walk on a street at Ginza shopping district in Tokyo, Japan, March 31, 2016. (Photo by Yuya Shino/Reuters)

Lucie Clayton instructs pupils in the art of correct posture by balancing a glass and book on their heads at her finishing school in Old Cavendish Street, London. (Photo by William Vanderson/Fox Photos/Getty Images). 25th November 1936

Kazakh troops march during a parade of the armed forces to mark the Defender of the Fatherland Day in Astana, May 7, 2014. (Photo by Mukhtar Kholdorbekov/Reuters)

“The Tasmanian devil (Sarcophilus harrisii) is a carnivorous marsupial of the family Dasyuridae now found in the wild only in the Australian island state of Tasmania. The size of a small dog, it became the largest carnivorous marsupial in the world following the extinction of the thylacine in 1936. It is characterised by its stocky and muscular build, black fur, pungent odour, extremely loud and disturbing screech, keen sense of smell, and ferocity when feeding”. – Wikipedia. Photo: A Tasmanian Devil bears it's teeth at a quarantine facility August 31, 2005 in Hobart, Australia. (Photo by Ian Waldie/Getty Images)

A leopard leaps into a muddy waterhole to catch a fish on August 13, 2015, in the Savuti Channel in Botswana. A leopard leaps into a muddy waterhole to catch a fish in the Savuti Channel in Botswana. The spotted predator stood poised waiting for a fish to appear – before leaping in ferociously with lightening reflexes. Coated in a layer of thick dark mud the big cat emerged from the water clutching the fish in its jaws. The fishing leopards of Savuti are known for their unique skills in catching fish – but have rarely been photographed. (Photo by Greatstock/Barcroft Media)