A passenger takes off his pants as others not wearing pants dance while waiting for a subway train during the “No Pants Subway Ride” in Mexico City, Mexico, February 21, 2016. The event is an annual flash mob and occurs in different cities around the world, according to its organisers. (Photo by Carlos Jasso/Reuters)

Ghanaian fans take a selfie prior to a Group G football match between Germany and Ghana at the Castelao Stadium in Fortaleza during the 2014 FIFA World Cup on June 21, 2014. (Photo by Patrik Stollarz/AFP Photo)

A Siberian tiger at a photographer for getting too much in its face during the presentation of two new Siberian tigers at Cabarceno Natural Reserve in Cabarceno, northern Spain, 21 July 2014. (Photo by Pedro Puente Hoyos/EPA)

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)

Arnold Schwarzenegger gives a thumbs up as he arrives for the Europe premiere of his new movie 'Terminator: Genisys' in Berlin, Germany, Sunday, June 21, 2015. (AP Photo/Michael Sohn)

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)

Riot policemen launch tears gas canisters during clashes with coca growers from Yungas in La Paz, Bolivia February 21, 2017. (Photo by David Mercado/Reuters)