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 couple take photographs alongside the National Monument on Calton Hill, Edinburgh on Wednesday January 5, 2022, ahead of First Minister Nicola Sturgeon's update to the Scottish Parliament on the Covid-19 situation as the Omicron variant sweeps across the country. (Photo by Jane Barlow/PA Images via Getty Images)

The Heavens opened as students from Wells Blue school year 13 pupils arrived at The Bishop's Palace in Wells, Somerset on June 30, 2022 for their end of year school prom. (Photo by Jason Bryant/Apex News)

A Highland Cow at sunset on the edge of the Marlborough Downs, Wiltshire, United Kingdom on October 18, 2020. (Photo by David White/PictureExclusive)

Lucy Blacker from Australia takes to the water at the 40 Foot for a Christmas Day Swim in Ireland on December 25, 2022. (Photo by Alan Betson/The Irish Times)

An old car passes by while dark clouds are seen due to the tropical storm Idalia in Havana, on August 28, 2023. (Photo by Yamil Lage/AFP Photo)

Planned improvements to Rio’s favelas have meant increases in rent, forcing the poorest families into squatting in unoccupied buildings. Photographer Tariq Zaidi visits the Mangueira community favela, less than 1km from the showpiece Maracanã stadium, to see what life is like for the women living there. Here: Victoria, 12, at her home in Mangueira. (Photo by Tariq Zaidi/The Guardian)

Camels graze in front of a spacecraft tracking station ahead of the Soyuz MS-10 upcoming launch at the Baikonur Cosmodrome, Kazakhstan, October 9, 2018. (Photo by Shamil Zhumatov/Reuters)