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)

Drinkers celebrated on the last Friday before Christmas in York, United Kingdom on December 18, 2020. Black Eye Friday, affectionately named for its tendency to prompt drink-fuelled punch ups as the Christmas cheer spills over, has been dampened this year by the global coronavirus pandemic shutting bars and banning socialising. (Photo by Nb press ltd)

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)

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)

Jan Agha, 49, an Afghan hunter, tries to catch his crane at a field in Bagram, Parwan province, Afghanistan on April 10, 2019. As the early morning light breaks over the plain north of Kabul, bird hunter Jan Agha checks his snares as he has done for the past 30 years, hoping to catch a crane, using a tethered bird to lure others down to the nets. (Photo by Mohammad Ismail/Reuters)

July gestures next to her boyfriend Jason Schaller while they are suspended from hooks pierced through their skins by professional body artist Wei Yilaien at a bar in Shanghai, China September 16, 2018. “I like being unique and I don't like doing things that many people are aware of and would accept”, said Wei, 24, who staged the show of extreme body piercing in China's normally buttoned down financial capital. (Photo by Aly Song/Reuters)

(L-R) Canadian actor Patrick J. Adams as Michael Ross and American member of the British royal family and a former actress Meghan Markle as Rachel Zane at “Breakfast, Lunch and Dinner”, Episode 402 in April 2014. (Photo by Ian Watson/USA Network/NBCU Photo Bank/NBCUniversal via Getty Images)