A street food vendor waits for customers on a footpath in New Delhi, India, November 27, 2018. (Photo by Anushree Fadnavis/Reuters)

Indonesian child jockey Egi, 8, poses for photographs as he participates in a traditional horse race marking Indonesia's 70th independence anniversary, in Bima, West Nusa Tenggara province, Indonesia, 08 August 2015. Horse racing is the traditional sport in the area and a cultural heritage which continues to be preserved by the people of Bima, a small city on the east side of Sumbawa island. Similar races also held in Sumbawa Besar regency and Dompu regency. (Photo by Mast Irham/EPA)

An Afghan Hound waits in the benching area during the Daytime Session in the Breed Judging across the Hound, Toy, Non-Sporting and Herding groups at the 143rd Annual Westminster Kennel Club Dog Show at Pier 92/94 in New York City on February 11, 2019. (Photo by Timothy A. Clary/AFP Photo)

Canadian actress Nina Dobrev needs an umbrella whilst leaving her hotel in Paris, France on March 4, 2019. (Photo by Splash News and Pictures)

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)

View of the Villarrica volcano taken from Pucon, some 800 kilometres south of Santiago, showing signs of activity on December 06, 2017. (Photo by Christian Miranda/AFP Photo)

Pascal Martinot-Lagarde, of France, celebrates his bronze medal in the men's 110 meter hurdles final at the World Athletics Championships in Doha, Qatar, Wednesday, October 2, 2019. (Photo by Petr David Josek/AP Photo)

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)