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 Saudi trader wears a mask as he monitors stock information at the Saudi stock market in Riyadh, Saudi Arabia on August 25, 2020. (Photo by Ahmed Yosri/Reuters)

A young man wears a mask on the right side of his head as he stands on a bridge with the European Central Bank at left in Frankfurt, Germany, Thursday, October 29, 2020. (Photo by Michael Probst/AP Photo)

Vehicles move past a man wearing a protective mask against COVID-19 as he waits for the bus in Karachi, Pakistan on December 11, 2020. (Photo by Akhtar Soomro/Reuters)

A male elephant named Mahadevan is tied in a truck as he is being transported for an annual temple festival in Kochi, India, March 10, 2020. (Photo by Sivaram V/Reuters)

Nermin Halilagic, 38, poses with kitchen utensils in Bihac, Bosnia and Herzegovina, January 23, 2017. Halilagic discovered earlier this year that he had the unusual ability to attach items to his body using what he says is a special energy radiated from his body. (Photo by Dado Ruvic/Reuters)

A woman prays as she touches the carcass of a male elephant after he, according to forest officials, was electrocuted early morning in a paddy field on the outskirts of Guwahati, India, June 20, 2017. (Photo by Anuwar Hazarika/Reuters)

Alligator trapper Mark Whitmire prepares an alligator he caught in a lagoon on a golf course to relocate it to a more natural environment in Orlando, Florida, U.S., June 19, 2016. (Photo by Carlo Allegri/Reuters)