A person walks through the Brooklyn Bridge during a snow storm, amid the coronavirus disease (COVID-19) pandemic, in New York City, New York, U.S., February 1, 2021. (Photo by Brendan McDermid/Reuters)

The moon rises behind Reunion Tower in downtown Dallas, Sunday evening, November 13, 2016. On Monday the supermoon will be the closest full moon to earth since 1948, and it won't be as close again until 2034. (Photo by Tom Fox/The Dallas Morning News via AP Photo)

Blanka Vlasic of Croatia and Team Europe celebrates a clearance in the women's high jump during the IAAF/VTB Continental Cup at the Stadion Poljud on September 5, 2010 in Split, Croatia. (Photo by Michael Steele/Getty Images)

Runners rest inside Kim Il Sung Stadium in Pyongyang, North Korea on Sunday, April 14, 2013. North Korea hosted the 26th Mangyongdae Prize Marathon to mark the upcoming April 15, 2013 birthday of the late leader Kim Il Sung. (Photo by Alexander F. Yuan/AP Photo)

Artwork by Ruth Bellotti & Steve Rosewell called “Soldier Scale 1:1” is seen at the 2008 Sculpture by the Sea launch at Mark's Park, Bondi on October 15, 2008 in Sydney, Australia. (Photo by Gaye Gerard/Getty Images)

Aerial photo taken on March 4, 2017 shows cole flower fields in Luoping County, southwest China's Yunnan Province. (Photo by Xinhua/Barcroft Images)

French model Tiffany Fournier poses for a digital presentation as part of the spring/summer 2021 collections for the Polish fashion house La Metamorphose, in Paris, France, September 26, 2020. (Photo by Charles Platiau/Reuters)

Behaviour: Mammals category. Giant Gathering by Tony Wu, USA. Dozens of sperm whales mingled noisily off Sri Lanka’s northeast coast, stacked as far down as Tony could see. This was a congregation of dozens of social units, like a gathering of the clans. Aggregations like this could be a critical part of the whales’ rich social lives but are rarely reported. Some two thirds of the population was wiped out before commercial whaling was banned in 1986. This kind of major gathering could be “a sign that populations are recovering”, says Tony. (Photo by Tony Wu/Wildlife Photographer of the Year 2017)