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)

People pose for photos in the snow in the Manhattan borough of New York City, New York, U.S., December 2, 2019. (Photo by Carlo Allegri/Reuters)

A fisherman with a close bond to cormorants uses the flock of birds to catch big fish in Li river in Guilin, China. The aquatic birds can be seen perching on a bamboo raft before swooping into the calm water to grasp hold of prey. (Photo by Julia Wimmerlin/Solnet News & Photo Agency)

A Palestinian fighter from Ezz-Al Din Al-Qassam Brigades, the armed wing of the Hamas movement, checks debris at the site of an Israeli air strike in Khan Yunis in the southern Gaza Strip on December 26, 2019. (Photo by Said Khatib/AFP Photo)

A couple shares a light moment in a Mass Transit Railway (MTR) subway train in Hong Kong, China on August 28, 2019. (Photo by Anushree Fadnavis/Reuters)

A traffic police officer directs traffic in Mohe City, northeast China's Heilongjiang Province, December 29, 2019. Temperatures in Mohe, “north pole” of China, often stand at below minus 40 degrees Celsius in winter mornings. Photo by Yang Siqi/Xinhua News Agency/Alamy Live News)

Monkeys sit along a street during a snowfall in Ayubia, some 75 km north of Islamabad, Pakistan on January 7, 2020. (Photo by Aamir Qureshi/AFP Photo)

Medical staff members wearing protective clothing to help stop the spread of a deadly virus which began in the city, arrive with a patient at the Wuhan Red Cross Hospital in Wuhan on January 25, 2020. The Chinese army deployed medical specialists on January 25 to the epicentre of a spiralling viral outbreak that has killed 41 people and spread around the world, as millions spent their normally festive Lunar New Year holiday under lockdown. (Photo by Hector Retamal/AFP Photo)