A man hugs a child at the Santuario de Nuestra Senora de Guadalupe during a celebration on the Virgin of Guadalupe Day in Guatemala City, December 12, 2015. According to Catholic believers, December 12 marks the anniversary of the apparition of the Virgin of Guadalupe at the Cerro del Tepeyac in Mexico. (Photo by Jorge Dan Lopez/Reuters)

Members of the Women's veteran movement take part in the March of Defenders of Ukraine as part of Ukraine's Independence Day celebrations, in Kyiv, Ukraine on August 24, 2020. (Photo by Gleb Garanich/Reuters)

A medical worker in protective gear sprays mist on her colleague during a hot day at an outdoor clinic for coronavirus tests at a public health facility in the southwestern city of Gwangju, South Korea, 05 June 2020. (Photo by Yonhap/EPA/EFE)

A shopper gets caught in a heavy downpour of rain on Oxford Street, London on June 27, 2020, as sunshine and showers are forecast for much of England and Wales on Saturday, with temperatures expected to hover around 22°C (71.6F). (Photo by Dominic Lipinski/PA Images via Getty Images)

British underwater photographer of the year 2021, British waters wide angle category winner and My Backyard category winner. While You Sleep by Mark Kirkland (United Kingdom), common frog taken in Malls Mire, Glasgow, Scotland. (Photo by Mark Kirkland/Underwater Photographer of the Year 2021)

People protest at the Boston Free Speech Rally in Boston, USA on August 19. 2017. With the Boston Free Speech rally was closed to the media (despite the Boston Common being a public space), a lot of the media’s coverage centred on the tensions within the larger counter-protest. (Photo by Stephanie Keith/Reuters)

A Boeing 777-300 from Swiss International Airlines lands on a foggy morning at Zurich Airport, on Friday, October 13, 2017, in Zurich, Switzerland. The high humidity renders the air vortex visible. (Photo by Christian Merz/Keystone via AP 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)