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 young girl from the Makonde ethnic group wearing earth makeup on her facen, a beauty symbol, carries a baby on her back as she poses for pictures in the community of Marupa, a relocation center for internally displaced families in the Chiure district, on February 23, 2021. Thousands of families from different districts of the Cabo Delgado province who have been displaced have been located by the government in different areas of the province. (Photo by Alfredo Zuniga/AFP Photo)

Attnedees dressed in Zombie outfits walk down the Gaslamp Quarter outside of the 2015 Comic-Con International in San Diego, California July 8, 2015. (Photo by Sandy Huffaker/Reuters)

A dog jumps into a swimming pool to retrieve a ball during the Chatsworth House Country Fair near Edensor, Britain on August 31, 2018. (Photo by Darren Staples/Reuters)

For a long time the laws of Canada have explicitly banned gambling in any form. This may be the reason why the country does not have so many gambling establishments as the USA - but their quality surely makes up for the quantity. The first Canadian casino was opened in Dawson City, Yukon, in 1972 - it was the first one after gambling has been banned in the country in 1892. The Diamond Tooth Gertie's Gambling Casino did not operate for long, though. The first permanent commercial casino was opened in 1989, and it was the first of many - there are currently 75 casinos operating on Canadian soil.

Japanese artist Mami Kiyoshi has spent 15 years creating vivid portraits of people surrounded by their belongings – from wine bottles and violins to the odd stray pet. Mami Kiyoshi’s ongoing series “New Reading Portraits” is, in part, a nod to the mise-en-scène found in traditional woodcut printing. Here: Sakura and Kazuhiro, Tokyo, 2015. (Photo by Mami Kiyoshi/Galerie Annie Gabrielli/The Guardian)

A girl jumps over a campfire while celebrating Ivan Kupala Night, a traditional Slavic holiday not far from Kiev on July 6, 2013. During the celebration, originating in pagan times, people plait wreaths, jump over fires, and swim naked. (Photo by Sergei Supinsky/AFP Photo)

Thomas jumps into the water from a spring board at a public swimming pool in Mengen, Germany, 28 August 2016. (Photo by Thomas Warnack/EPA)