A fan waves a Brazilian flag before the arrival of the Olympic torch ahead of the Rio 2016 Olympic Games on August 2, 2016 in Sao Goncalo, Rio de Janeiro state, Brazil. The torch will arrive in the city of Rio tomorrow and the Games commence on August 5. (Photo by Mario Tama/Getty Images)

An Afghan Army soldier secures the hill overlooking the Kart-e Sakhi mosque in Kabul, Afghanistan, Wednesday, March 20, 2013. Thousands of Afghans will celebrate Nowruz on Thursday, March 21, 2013 to mark the first day of spring and the beginning of the year on the Iranian calendar. (Photo by Ahmad Jamshid/AP Photo)

Two people wearing animal costumes join others as people gather to celebrate the Winter Solstice at Stonehenge in England Tuesday December 22, 2015. The winter solstice is celebrated by many people around the world as the beginning of the return of the sun. (Photo by Ben Birchall/PA Wire via AP Photo)

An artist applies henna on the hand or a woman during the Hindu festival of lights, Diwali, in Taipei, Taiwan, Thursday, November 4, 2021. Millions of people across Asia are celebrating the Hindu festival of Diwali, which symbolizes new beginnings and the triumph of good over evil and light over darkness. (Photo by Chiang Ying-ying/AP Photo)

A reveller participates in a parade during a carnival to mark the annual Orthodox St. Vasilij Day, the beginning of the Orthodox New Year, in the village of Vevcani, North Macedonia, in this still image taken from a picture, on January 13, 2025. (Photo by Ognen Teofilovski/Reuters)

Models promote the game “Diamond Dogs” during the Gamescom 2015 fair in Cologne, Germany August 5, 2015. Hundreds of thousands of visitors will enjoy one of the world's largest computer and video game events until Sunday. (Photo by Kai Pfaffenbach/Reuters)

Nyibol Lual, 13 years old, helps her family to prepare the land for cultivation on May 31, 2017, in Panthau, Northern Bahr al Ghazal, South Sudan. The family has a small land where they cultivate sorghum. An estimated 63 per cent of the population in Northern Bahr al Ghazal is experiencing severe food insecurity, according to the latest Integrated Food Security Phase Classification (IPC) report. The situation is particularly bad in Aweil West and Aweil South counties, where the exhaustion of household food stocks and growing dependence on financially inaccessible markets have left the population facing Emergency levels of food insecurity. (Photo by Albert Gonzalez Farran/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)