Britain's Camilla, Duchess of Cornwall watches a performance during a salsa school visit in Havana, Cuba March 26, 2019. (Photo by Phil Noble/Reuters)

A vintage car sits in flood water on March 20, 2019 in Hamburg, Iowa. Although flood water in the town has started to recede many homes and businesses remain surrounded by water. Several Midwest states are battling some of the worst flooding they have experienced in decades as rain and snow melt from the recent “bomb cyclone” has inundated rivers and streams. At least three deaths have been linked to the flooding. (Photo by Scott Olson/Getty Images)

A man looks at a photograph by French photographer Robert Doisneau entitled “The Fate Line: Pablo Picasso at Vallauris, 1952” during the presentation of the photo-exhibition “Picasso, photographer's gaze”, on June 5, 2019 at the Picasso Museum in Barcelona. (Photo by Lluis Gene/AFP Photo)

Drag Queens set a Guinness World Record for the longest feather boa at 1.2 miles, along 42 St, in Times Square in New York, U.S., June 20, 2019. (Photo by Eduardo Munoz/Reuters)

Participants dance during the Water Gun Festival on July 07, 2019 in Seoul, South Korea. Thousands of people enjoyed the annual festival which is being held over the weekend during the scorching heat summer in Korea. (Photo by Chung Sung-Jun/Getty Images)

A “mozos”, is caught by the horn of a bull of Miura ranch during the last “encierro”, or running-with-the-bulls, of the Sanfermines festivities in Pamplona, Spain, 14 July 2019. (Photo by Daniel Fernandez/EPA/EFE)

Relatives of community leader Josemano “Badou” Victorieux, one of the victims of clashes with the Police, cry during his funeral in Port-au-Prince, Haiti, 16 October 2019. The protest movement in Haiti completes a month with no sign of remitting and without the President, Jovenel Moise, yielding to the voices that require him to resign. (Photo by Orlando Barria/EPA/EFE)

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)