This photo taken on February 26, 2019 shows an aerial view of a tea field in Zhangping in China's eastern Fujian province. (Photo by AFP Photo/China Stringer Network)

Darth Vader balloon above Clifton Suspension Bridge during the hot air balloons mass ascent at sunrise on the first day of the Bristol International Balloon Fiesta on August 8, 2019 in Bristol, England. The Bristol International Balloon Fiesta is Europe's largest annual meeting of hot air balloons, attracting over 130 hot air balloons from across the globe. (Photo by Finnbarr Webster/Getty Images)

In this August 26, 2019 photo, children of the Nambikwara Sarare tribe climb trees as they play in their indigenous reserve in the southwestern Amazon, near Conquista D'Oeste, in the Brazilian state of Mato Grosso. About 98% of all Brazil’s indigenous lands lie within the Amazon. (Photo by Andre Penner/AP 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)

Members of the China Disabled Peoples Performing Art Troupe perform “My Dream” at Jorge Eliecer Gaitan Theater in Bogota on August 30, 2017. China Disabled People's Performing Art Troupe Company composed of artists with some hearing, mental, motor, visual or speech disabilities, was founded in 1987 and is currently Honorary and Goodwill Ambassadors of Unesco for its great example of inclusion. (Photo by John Vizcaino/AFP Photo)

The “Rabid Transit” Burning Man art car erupts with flames from it's onboard propane poofers during the 4th day of the annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S., August 31, 2017. (Photo by Jim Bourg/Reuters)

Eva Longoria Farmer Visits "The Tonight Show Starring Jimmy Fallon" at Rockefeller Center on November 24, 2015 in New York City. (Photo by Theo Wargo/NBC/Getty Images for "The Tonight Show Starring Jimmy Fallon")

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)