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 man holds a metal bar as a weapon during a training day for former soldiers and volunteers train in a makeshift camp in the outskirts of Port-au-Prince, Haiti, October 28, 2015. Haiti disbanded its abusive armed forces two decades ago but uniformed veterans and young recruits are resurfacing to add another destabilising factor to the volatile Caribbean nation already dealing with a political vacuum. (Photo by Andres Martinez Casares/Reuters)

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)

Winton Elementary fifth graders Juliana Ragan, from left, Chloe Windsor and Paisley Ganske wait backstage for their turn to perform as the Andrew Sisters during the Pearl Harbor/Veterans assembly at the school on Monday, December 7, 2015, in Coeur d'Alene, Idaho. Dec. 7 is the 74th anniversary of the Japanese bombing of Pearl Harbor. (Photo by Kathy Plonka/The Spokesman-Review via AP Photo)

Zhang Shifan's sixth-generation facekinis in Shandong Province, Qingdao, East China. A woman credited with inventing the bizarre swimwear known as the “facekini” has now proudly presented the sixth generation of the iconic beach clothing. The new facekini models are not only more comfortable, they also come in a wider variety of colours and patterns, bringing both style and practicality to beach-goers in Qingdao City, in East China's Shandong Province, who fear tan lines. (Photo by CEN)

Smoke plumes rise from Mount Etna, one of the most active volcanoes in the world in Sicily, Italy on June 28, 2016. (Photo by Etna Walk/Rex Feature/Shutterstock)

Russian model and television personality Irina Shayk teases her appearance in the Savage X Fenty show in the first decade of November 2022. (Photo by irinashayk/Instagram)

A Ukrainian serviceman kisses his partner at the train station in Kramatorsk, Ukraine, Thursday, March 23, 2023. (Photo by Evgeniy Maloletka/AP Photo)