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)

A tourist poses on the glass-bottom bridge at Zhangjiajie Grand Canyon on August 20, 2016 in Zhangjiajie, Hunan Province of China. The Zhangjiajie Grand Canyon's glass-bottomed bridge welcame its trial operation on Saturday and about 8,000 tourists crowded to view the grand glass bridge. (Photo by VCG/VCG via Getty Images)

Ex-Pussycat Dolls singer Nicole Scherzinger and The Cuban Brothers perform at the de Grisogono party during the 71st annual Cannes Film Festival at Villa des Oliviers on May 15, 2018 in Cap d'Antibes, France. (Photo by Goff Photos)

An Afghan woman walks with a child in the old city of Herat province, Afghanistan on October 15, 2018. (Photo by Mohammad Ismail/Reuters)

Iraqi teenagers swim in waste water from the nearby Tuweitha nuclear facility near Baghdad, Iraq on May 28, 2003. Iraqis are consuming contaminated water unaware of the dangerous pollutants that can cause severe ill health. (Photo by Damir Sagolj/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 wrestling camel adorned with colourful ornaments takes part in the Camel Beauty Contest ahead of the annual 40th Efes Selcuk Camel Wrestling Festival, in the Aegean town of Selcuk, near Izmir, Turkey on January 15, 2022. (Photo by Murad Sezer/Reuters)

Natali Sevriukova reacts next to her house following a rocket attack in the city of Kyiv, Ukraine, Friday, February 25, 2022. (Photo by Emilio Morenatti/AP Photo)