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 person wearing a face mask holds a cat on Swanston Street after cases of the coronavirus were confirmed in Melbourne, Victoria, Australia, January 29, 2020. (Photo by Andrew Kelly/Reuters)

A sanitation worker fumigates using sodium hypochlorite in an archive room to fight the spread of the coronavirus disease (COVID-19) in the Milimani commercial courts in Nairobi, Kenya, July 17, 2020. (Photo by Baz Ratner/Reuters)

A Viet Cong suspect holds his hands up after a Vietnamese Ranger from the 21st Vietnam Infantry Division routed him from his hiding place. (Photo by Keystone/Getty Images). 7th November 1967

An Egyptian security guard screams at people as medics bring in a stretcher to carry the wounded after the attack which killed President Anwar Sadat, October 6, 1981, as he watched a military parade. (Photo by AP Photo)

A Pataxo woman listens to her cell phone as she waits for the start of the Indigenous people's meeting with Brazil's former President Luiz Inacio Lula da Silva, as part of the 18th annual Free Land Indigenous Camp, in Brasilia, Brazil, Tuesday, April 12, 2022. (Photo by Eraldo Peres/AP Photo)

American actress, dancer, and singer Ariana DeBose arrives at the 75th annual Tony Awards on Sunday, June 12, 2022, at Radio City Music Hall in New York. (Photo by Evan Agostini/Invision/AP Photo)

Belgian-British teenager Zara Rutherford closes the canopy of her Shark Ultralight airplane as she prepares to take off at the Kortrijk-Wevelgem airfield in Wevelgem, Belgium, Wednesday, August 18, 2021. A Belgian-British teenager took to the skies Wednesday in her quest to become the youngest woman to fly around the world solo. Nineteen-year-old Zara Rutherford took off from an airstrip in Wevelgem, Belgium, in an ultralight plane looking to break the record set by American aviator Shaesta Waiz, who set the world benchmark at age 30 in 2017. (Photo by Virginia Mayo/AP Photo)