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)

A female referee counts as member of Uganda's Soft Ground Wrestling is pinned to the ground during a training session at their camp in Mukono on February 28, 202. Uganda's Soft Ground Wrestling is getting attention worldwide and becoming an Internet sensation. Members showcase their wrestling skills on their YouTube channel, performing inside makeshift bamboo ring posts with string ropes and soil. Currently, Soft Ground Wrestling has 200 members, most of them from unprivileged backgrounds, and include both men and women training vigorously as they dream of becoming professional wrestlers. (Photo by Badru Katumba/AFP Photo)

A Thai devotee in a state of trance screams while holy water is sprayed as thousands race towards the edifice of the founder monk during the annual Tattoo fesitval at Wat Bang Phra on March 7, 2009 in Nakhom Pathom, Thailand. Some men take on the characteristics of sacred animals that have been carved onto their skin. Thousands of believers from all over Thailand come to take part in one of the country's most bizarre festivals about 50 miles outside Bangkok to pay respect to the temple's monks who are master tattooist. In Thai culture the tattoo or Thai word sak yant is worn as a symbol of spiritual and physical protection, many believe that the tattoo have mystical powers. Many tattoo fanatics choose to have monkeys and tigers as well as the Khmer/Cambodia ancient script on their bodies. (Photo Paula Bronstein/Getty Images)

“Wells Cathedral is a Church of England cathedral in Wells, Somerset, England. Built between 1175 and 1490, Wells Cathedral has been described as “the most poetic of the English Cathedrals”. The Wells clock, an astronomical clock, is located in the north transept. The surviving mechanism, dated to between 1386 and 1392, was replaced in the 19th century, and was eventually moved to the Science Museum in London, where it continues to operate. It is the second-oldest surviving clock in England”. – Wikipedia

Photo: The clock face of world's oldest continually-working mechanical clock is seen as it is hand wound for the very last time on August 21, 2010 in Wells, England. (Photo by Matt Cardy/Getty Images)

“The Great Barrier Reef is one of the most important sea turtle habitats in the world, with Lady Elliot Island being a key part of that habitat. Every year between November and March the green and loggerhead turtles lumber up the same beach on which they were born more than 50 years ago. These turtles nest on Lady Elliot Island up to nine times in a season, laying between 80 and 120 eggs per clutch. About eight weeks later, young hatchlings leave their nests and head towards the ocean (January to April)”. – Wikipedia

Photo: A Hawksbill sea turtle is seen swimming on January 15, 2012 in Lady Elliot Island, Australia. (Photo by Mark Kolbe/Getty Images)

“A Hadaka Matsuri (“Naked Festival”) is a type of Japanese festival, or matsuri, in which participants wear a minimum amount of clothing; usually just a Japanese loincloth (called fundoshi), sometimes with a short happi coat, and rarely completely naked. Whatever the clothing, it is considered to be above vulgar, or everyday, undergarments, and on the level of holy Japanese shrine attire. Naked festivals are held in dozens of places throughout Japan every year, usually in the summer or winter. The most famous festival is held in Okayama, where the festival originated. Every year, over 9,000 men participate in this festival”. – Wikipedia

Photo: Japanese men wear loincloths as they splash about in freezing cold water during Saidaiji Naked Festival, at Saidaiji Temple on February 18, 2012 in Okayama, Japan. (Photo by Buddhika Weerasinghe/Getty Images)

Boys walk home for lunch from school in the village of Kogelo, west of Kenya's capital Nairobi, July 16, 2015. U.S. President Barack Obama visits Kenya and Ethiopia later this month. His ancestral home of Kogelo is home to Sarah Hussein Obama, his step-grandmother. The Kenyan village, burial place of Obama's father, features an open-pit goldmine, a pork butcher's, a school named after their most famous son and outdoor market stalls. Villagers get around by motorbike taxi or on foot while a donkey-cart transports water. Children, some of them named Obama in honour of the President, walk to and from school together. (Photo by Thomas Mukoya/Reuters)

Downhill bikers Kemal Mulic (R-L), Tarik Hadzic and Kamer Kolar train on the disused bobsled track from the 1984 Sarajevo Winter Olympics on Trebevic mountain near Sarajevo, Bosnia and Herzegovina, August 8, 2015. Abandoned and left to crumble into oblivion, most of the 1984 Winter Olympic venues in Bosnia's capital Sarajevo have been reduced to rubble by neglect as much as the 1990s conflict that tore apart the former Yugoslavia. (Photo by Dado Ruvic/Reuters)