Rescue workers help the injured at the site of a multi-storey building collapse in the capital Nairobi, Kenya Sunday, January 4, 2015. The residential building in the Huruma neighborhood of Nairobi collapsed on Sunday and according to the Kenya Red Cross, a dozen people have so far been rescued but an unknown number are still feared trapped. (Photo by AP Photo)

A eunuch dances during a rally to mark the congregation of thousands of eunuchs from different parts of India, in Jammu, India, Friday, March 13, 2015. The term eunuchs is used in India to describe transvestites, transsexuals and others who identify themselves as neither male nor female but as a member of a third gender. They traditionally survive by begging, dancing at weddings or blessing newborn babies and are frequently subjected to discrimination. (Photo by Channi Anand/AP Photo)

A model walks down the runway at the 13th China International Young Fashion Designers Contest during China Fashion Week on March 25, 2005 in Beijing, China. (Photo by China Photos/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)

Irwan bathes a domesticated crocodile at his house in Bogor, Indonesia on January 22, 2018. Irwan found it as a baby and now it has been living with Irwans family for 20 years. Indonesia is known as a hotbed of exotic pet domestication and trade. People have been known to keep endangered animals such as slow lorises, eagles and pangolins, angering conservationists and animal rights activists. (Photo by Eko Siswono Toyudho/Anadolu Agency/Getty Images)

China's Gu Ailing Eileen waits to see her score as she competes in the freestyle skiing women's freeski slopestyle final run during the Beijing 2022 Winter Olympic Games at the Genting Snow Park H & S Stadium in Zhangjiakou on February 15, 2022. (Photo by Marco Bertorello/AFP Photo)

Botswana's Ross Branch competes during the Abu Dhabi Desert Challenge stage two on March 7, 2022. (Photo by Edoardo Bauer/AFP 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)