Viking re-enactors representing the rival armies of the Vikings and Anglo-Saxons skirmish near Clifford’s Tower during the Jorvik Viking Festival on February 23, 2019 in York, England. The annual Jorvik Viking Festival held in York is recognised as the largest event of its kind in Europe. This year the festival remembers the role that the Viking women played during those turbulent times. (Photo by Christopher Thomond/The Guardian)

A brick factory workers stack bricks on carts in Dhaka, Bangladesh, January 9, 2019. (Photo by Mohammad Ponir Hossain/Reuters)

People take part in a gay pride parade in Warsaw, Poland, on Saturday, June 8, 2019. The Equality Parade is the largest gay pride parade in central and Eastern Europe. It brought thousands of people to the streets of Warsaw at a time when the LGBT rights movement in Poland is targeted by hate speeches and a government campaign depicting it as a threat to families and society. (Photo by Czarek Sokolowski/AP Photo)

A man passes by a wall with graffiti in Beirut, Lebanon, on May 29, 2019. (Photo by Bilal Jawich/Xinhua News Agency/Alamy Live News)

An Indian Sadhu, or Hindu holy man, performs a yoga position on International Yoga Day at Kamakhya temple in Gauhati, India, Friday, June 21, 2019. (Photo by Anupam Nath/AP Photo)

Female members of the Hammer tribe from the village of Turmi, situated in southern Ethiopia near the Kenyan border, dance as part of a ritual called the “bull jumping ceremony” that takes place during the passage of a young boy to adulthood, in Turmi, Ethiopia, 25 September 2019. (Photo by Stéphanie Lecocq/EPA/EFE)

Prince Philip, Duke of Edinburgh practicing his bicycle polo technique, Windsor Great Park, Berkshire, 1964. (Photo by Norman Potter/Daily Express/Hulton Archive/Getty Images)

Bloodthirsty by Thomas P. Peschak, Germany/South Africa — winner, Behaviour: birds. When rations run short on Wolf Island, in the remote northern Galápagos, the sharp-beaked ground finches become vampires. Their sitting targets are Nazca boobies and other large birds. The finches rely on a scant diet of seeds and insects, which regularly dries up, so they drink blood to survive. ‘I’ve seen more than half a dozen finches drinking from a single Nazca booby,’ says Tom. Rather than leave their nests the boobies tolerate the vampires, and the blood loss doesn’t seem to cause permanent harm. (Photo by Thomas P. Peschak/2018 Wildlife Photographer of the Year)