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)

Andrea Abarca, (C) leads an aerobics class in Los Guidos de Desamparados July 23, 2015. More than 300 women participated in a physical health program organized by Abarca, which aims to combat obesity and sedentary behavior in poor women living in a slum. The National Nutrition Survey shows that the Costa Rican population has 62.4 percent of adult men who are obese, while among women the percentage was 77.3, according to local media. (Photo by Juan Carlos Ulate/Reuters)

Palestinian Munir Shindi, 36, drives a replica of a 1927 Mercedes Gazelle that he built from scratch, on a street in Gaza City June 19, 2016. (Photo by Mohammed Salem/Reuters)

Two hippopotamus are fed with pumpkins at the Hanoi Zoo, in Hanoi, Vietnam, 25 October 2018. The zoo has been the home for more than 800 animals of over 90 different species, including three hippopotamus, since it was built in 1976. (Photo by Luong Thai Linh/EPA/EFE)

American actress Indya Moore attends the FOX/HULU Golden Globe Awards viewing party and post-show celebration at The Beverly Hilton Hotel on January 6, 2019 in Beverly Hills, California. (Photo by Rachel Murray/Getty Images for Hulu)

Female labourers wearing helmets take a break from laying underground electricity cables in Ahmedabad, India, March 7, 2016. (Photo by Amit Dave/Reuters)

US film star Elizabeth Taylor and her first husband Nick Hilton, of the hotelier family, on their wedding day.

People look at the lava flowing on Fagradalsfjall volcano in Iceland on Wednesday August 3, 2022, which is located 32 kilometers (20 miles) southwest of the capital of Reykjavik and close to the international Keflavik Airport. Authorities in Iceland say the volcano in the southwest of the country is erupting just eight months after its last eruption officially ended. (Photo by Marco Di Marco/AP Photo)