A dog walks past a mural by street artist Alex Martinez outside a shop which sells bags at Psiri area, central Athens, on Thursday, January 25, 2018. (Photo by Petros Giannakouris/AP Photo)

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)

Dancers perform the traditional “Diablada” or Dance of the Devils during the Carnival in Oruro, Bolivia, Saturday, February 10, 2018. Thousands of colorfully dressed dancers and musicians kick off Carnival celebrations in the Bolivian city of Oruro. (Photo by Juan Karita/AP Photo)

A young hunter rests next to his tamed golden eagle during an annual hunters competition at Almaty hippodrome, Kazakhstan February 9, 2018. (Photo by Shamil Zhumatov/Reuters)

A Geoffroy's Monk Saki is seen at the Parque de Las Leyendas zoo in Lima, Peru, February 14, 2018. (Photo by Guadalupe Pardo/Reuters)

Leslie Cliff and his wife Violet, English figure skating pair. Olympic games of Garmisch-Partenkirchen (Germany), 1936. (Photo by Roger Viollet Collection/Getty Images)

English lingerie and catwalk model and television personality Abbey Clancy seen attending Warner Music Brits after party in London, England on February 22, 2018. (Photo by Hewitt/SilverHub/Rex Features/Shutterstock)

Prince Philip, the Duke of Edinburgh meets members of the cast of “Chicago” during a visit to the Adelphi Theatre in this March 4, 1999 file photo in London, England. (Photo by Anwar Hussein/Getty Images)