A man in “Red Army” garb hits the pavement during a simulated attack during a re-staging of part of the Long March in Jinggangshan September 14, 2017. The scene brings alive an extraordinary chapter in China's history that established the supremacy of Chairman Mao Zedong and the Communist Party. Deep in the mountains of Jinggangshan in the southeastern province of Jiangxi, a classroom of bank tellers participates in an ideological boot camp that plays into Chinese President Xi Jinping's drive to further consolidate his grip on power. (Photo by Thomas Peter/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)

People react as a Canadian man wearing only a pair of shorts orders a drink from a fast food outlet in Gangneung Curling Centre on day 10 of the PyeongChang 2018 Winter Olympic Games on February 19, 2018 in Gangneung, South Korea. (Photo by Carl Court/Getty Images)

A boy plays with pelicans in Yoff, commune of Dakar, Senegal March 14, 2018. (Photo by Zohra Bensemra/Reuters)

Villagers from Jiexi Jiantan village perform a ritual of “Zha Laoye”, or “Cracking local spirits”, in Chaoshan, Guangdong Province, China, 10 February 2019. Jiexi Jiantan Village celebrates the annual custom of “Zha Laoye” where Laoye are local spirits. Every third day of the lunar New Year, statues of local spirits known as the “Thousand-mile Eye” Laoye and “Ear Following the Wind” Laoye are brought out to the village committee to receive incensed tea offered by believers. (Photo by EPA/EFE/ZNSEN)

In this April 16, 2019 photo, people wait to be given empty water containers and water purification pills during the first aid shipment from the Red Cross in Caracas, Venezuela. In late March, the Red Cross federation announced it would soon begin delivering assistance to an estimated 650,000 people and vowed that it would not accept interference from either side of the polarized country. (Photo by Ariana Cubillos/AP Photo)

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)

Participants from a North Korea military band perform during the Spasskaya Tower international military music festival in Red Square in Moscow, Russia, Friday, August 23, 2019. (Photo by Alexander Zemlianichenko/AP Photo)