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)

Manman Luk, a freelance model and make up artist, poses inside her 100-square-foot (9-square-metre) sub-divided unit, paying a monthly rent of HK4,700 ($606) in Hong Kong, China January 6, 2017. (Photo by Bobby Yip/Reuters)

The sky looked on fire this morning, as it made the clouds glow red, just before sunrise at Peterborough Rowing Lake, in Nene Park, UK on January 18, 2017. (Photo by Paul Marriott/Rex Features/Shutterstock)

In northwest Russia, in a small village called Alekhovshchina, Nadia Sablin's aunts spend the warmer months together in the family home and live as the family has always lived, chopping wood to heat the house and making their own clothes. Sablin's book of photographs, “Aunties: The Seven Summers of Alevtina and Ludmila”, is published by Duke University Press. Here: “Two-Handed Saw, 2014”. (Photo by Nadia Sablin)

Australian model Kate Fischer (Tziporah Malkah) poses with a Cointreau Ball to celebrate France’s founding anniversary in Sydney, Australia on July 14, 1996. (Photo by Getty Images)

Dan Luvisi reimagines beloved animated characters and turns them into grimy, twisted, hideous personas that may have just scarred us of our fondest memories from childhood forever. Photo: “The Cook”. (Photo by Dan Luvisi)

General Atmosphere at 2014 New York Comic Con – Day 3 at Jacob Javitz Center on October 11, 2014 in New York City. (Photo by Laura Cavanaugh/Getty Images)

Actress Ruby Rose, left, recipient of the Stephen F. Kolzak Award, hands her jacket to presenter Taylor Swift during the 27th Annual GLAAD Media Awards at the Beverly Hilton on Saturday, April 2, 2016, in Beverly Hills, Calif. (Photo by Chris Pizzello/Invision/AP Photo)