Khan, a five-year-old male White Bengal tiger, looks on inside an open-air cage at the Royev Ruchey zoo in Krasnoyarsk, Russia, October 21, 2016. (Photo by Ilya Naymushin/Reuters)

A man washes his horse as a woman bathes her son at concrete water pens under a flyover in a slum area in Kolkata, India October 21, 2016. (Photo by Rupak De Chowdhuri/Reuters)

A Ukrainian serviceman fires a 2S7 Pion self-propelled gun during military exercises near the village of Divychky in Kiev region, Ukraine, October 21, 2016. (Photo by Valentyn Ogirenko/Reuters)

A garbage collector looks for recyclable waste at a dump in Erbil, in Iraq's northern autonomous Kurdistan region, February 21, 2016. (Photo by Azad Lashkari/Reuters)

A cat receives acupuncture treatment in Shanghai, China on August 21, 2017. Traditional practitioners believe acupuncture of the body can stimulate blood circulation to promote healing and relieve some aches and pains. (Photo by Aly Song/Reuters)

Worshippers of the Black Christ of Portobelo look at the statue during the annual celebratory pilgrimage in Portobelo, in the province of Colon October 21, 2015. Thousands of devotees gather at the Festival of the Black Christ every year to celebrate Christ's miracles. (Photo by Carlos Jasso/Reuters)

Attendees dressed as Poison Ivy and Harley Quinn arrive for opening day of the annual Comic-Con International in San Diego, California, United States July 21, 2016. (Photo by Mike Blake/Reuters)

Merfolk gather at MerMania 2017, the world's largest gathering of amateur and professional mermaids and mermen in North Carloina, USA on January 21, 2017. (Photo by Brian Cahn/ZUMA Wire/Rex Features/Shutterstock)