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 woman visits the exhibition “Pop Air” at the Balloon Museum in Madrid, Spain, 22 March 2023. The exhibition, dedicated to balloons and inflatable arts, opened to the public in Madrid on 18 March and runs through 23 July 2023. (Photo by Alejandro Lopez/EPA)

Pupils from St Teilo’s Catholic Primary School in Tenby, South Wales, perform a scene from their Nativity play in the second decade of December 2023. The three kings, played by Jack Rigby, Santos Basilnomo and Tommy Leggett, pretended to follow a star on South Beach, a stone’s throw from the school. (Photo by Joann Randles/Cover Images)

Singers Britney Spears and Madonna share a kiss onstage during the 2003 MTV Video Music Awards at Radio City Music Hall on August 28, 2003 in New York City. (Photo by Dave Hogan/Getty Images)

Waves crash against the lighthouse in Seaham Harbour, County Durham in northeast England on Friday, November 24, 2023. (Photo by Owen Humphreys/PA Images via Getty Images)

A model presents a creation by designer Katy Nguyen during Vietnam International Fashion Week in Hanoi, Vietnam, Wednesday, November 1, 2017. (Photo by Hau Dinh/AP Photo)

Artwork by Ruth Bellotti & Steve Rosewell called “Soldier Scale 1:1” is seen at the 2008 Sculpture by the Sea launch at Mark's Park, Bondi on October 15, 2008 in Sydney, Australia. (Photo by Gaye Gerard/Getty Images)

Indian passengers travel on a local train in New Delhi, India, October 2017. Constructed in 1975 to bypass the crowded and passenger-heavy Old Delhi, New Delhi and Hazrat Nizamuddin railway stations, the railway line once used to be the lifeline of the capital. (Photo by Ankur Dutta/Barcroft Media)