In this photograph taken on February 18, 2016, Pakistani children ride on swings in the predominantly Pashtun Korangi District of Karachi. In a rundown district of Karachi, Rabia balks at a neighbour's proposal to vaccinate her children, demonstrating one of the biggest hurdles to eradicating polio in Pakistan by the end of the year: confused and frightened parents. (Photo by Asif Hassan/AFP Photo)

A chimpanzee looks in the direction of a camera at the Gut Aiderbichl Sanctuary for Traumatized Chimpanzees and other Primates in Gaenserndorf, near Vienna, 17 September 2018. 34 former laboratory chimpanzees of former Austrian pharmaceutical company Immuno AG spend their lives at the Gut Aiderbichl Sanctuary for Traumatized Chimpanzees and other Primates since 2009. (Photo by Christian Bruna/EPA/EFE)

An opposition supporter wearing a costume lies on the ground in front of riot police during a rally against Venezuelan President Nicolas Maduro's government and to commemorate the 59th anniversary of the end of the dictatorship of Marcos Perez Jimenez in Caracas, Venezuela January 23, 2017. The sign reads “Venezuelans starve. There is no food or medicine. The underworld kills us. Get out Maduro”. (Photo by Marco Bello/Reuters)

A man waits with his camel to take part in a camel decoration competition at the Nagaur Cattle Fair, where animals like camels, cows, horses, and bulls are brought to be sold or traded, in Nagaur, in the desert state of Rajasthan, India February 2, 2017. (Photo by Himanshu Sharma/Reuters)

Marion (L) and Nikola (R), members of the Sport Saber League, pose with their light sabers in front of the Eiffel tower in Paris, France, November 26, 2015. Three "Star Wars" fans opened the French Academy of the Sport Saber League in September 2015 due to the increase interest for light saber fighting and the upcoming movie "The Force Awakens" which will premier in Paris, December 16th, two days before its worldwide official release. (Photo by Charles Platiau/Reuters)

A competitor takes part in the 31st World Bog Snorkelling Championships, held annually at Llanwrtyd Wells in Wales, Britain August 28, 2016. Entrants must negotiate two lengths of a 60-yard trench through the peat bog in the quickest possible time without using any conventional swimming strokes. (Photo by Rebecca Naden/Reuters)

A charity runner dressed as Father Christmas steps out of a portable toilet ahead of the “Santa Run” charity fun run in Stockholm on December 10, 2017. Hundreds of participants dressed in Santa suits and wearing white beards ran through the streets of the old town in Stockholm in an all charity run. (Photo by Jonathan Nackstrand/AFP Photo)

5-year-old Rina Kumari rubs her eye while cracking stones on the banks of Mahananda river in Siliguri, northeast India, March 5, 2005. Over 400 million people in India live below the internationally agreed poverty line (living on less than US $1 per day). According to estimates, several hundred thousand children work as labourers and beg on the streets in India. (Photo by Desmond Boylan/Reuters)