A photographer tested the concentration of several pairs of dogs as he captured their reactions to treat time in a series of shots. Christian Vieler, 47, of Waltrop, Germany, has been a professional dog photographer since 2016. He came up with the idea of snapping two dogs catching treats simultaneously. Here: Basset Hounds. (Photo by Vieler Photography/Caters News Agency)

A zookeeper counts penguins through an observation window during the annual stocktake at ZSL London Zoo in central London on January 3, 2023. (Photo by Justin Tallis/AFP Photo)

A woman stumbes as people run down Oxford Street, London, Britain, November 24, 2017. Police are responding to reports of an incident at London's Oxford Circus Tube station and have urged the public to avoid the area. (Photo by Peter Nicholls/Reuters)

Daniela Burza, 45, wears a Nasty Woman t-shirt and a mask of U.S. Democratic presidential nominee Hillary Clinton as she competes during the Haunted Heats Halloween Surf Contest in Santa Monica, California, U.S., October 29, 2016. (Photo by Lucy Nicholson/Reuters)

A girl feeds a squirrel in Bolivar Square, in Caracas, Venezuela on June 4, 2024. (Photo by Gaby Oraa/Reuters)

A girl poses in her costume during a Halloween party at a mall in Quezon city, Metro Manila October 24, 2015. (Photo by Ezra Acayan/Reuters)

Indian artist Sudarsan Pattnaik works on a sand sculpture depicting drowned Syrian boy Aylan Kurdi at Puri beach, some 65 kilometers away from Bhubaneswar, on September 4, 2015. Charities helping refugees saw a surge in donations on September 4 across Europe as people shocked by the heart-rending images of a drowned Syrian boy on a Turkish beach dug deep to help out. The photos of the lifeless body of three-year-old Aylan Kurdi, lying on a beach in Bodrum, Turkey, have triggered a wave of emotion across the continent, despite deep divisions among European governments on how to deal with the crisis. (Photo by Asit Kumar/AFP Photo)

Participants compete in a wife-carrying championship in Tapiobicske, Hungary, August 7, 2021. Some 40 Hungarian husbands, with their wives on their backs, clambered over rough terrain on Saturday in the nation's second wife-carrying contest. (Photo by Marton Monus/Reuters)