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)

Marshalls try to get their hands on a streaker as golfers Michael Campbell of New Zealand and Paul McGinley of Ireland play the World Match Play final at Wentworth golf club some 20 miles west of London, 18 September 2005. Campbell won the title at the 17th hole. (Photo by Odd Andersen/AFP Photo)

Russian opposition leader, Alexei Navalny (C), reacts as the court delivers the verdict in his trial, in the city of Kirov, Russia, 18 July 2013. Alexei Navalny was sentenced to five years in jail for theft on Thursday, an unexpectedly tough punishment which supporters said proved President Vladimir Putin was a dictator ruling by repression. (Photo by Valentina Svistunova/EPA)

“Left behind” children Luo Hongni, 11 (L) and brother Luo Gan,10, carry flowers to be used as feed while doing chores in the fields on December 18, 2016 in Anshun, China. Like millions of Chinese children, the four Luo siblings are being raised by their grandparents in rural China as their parents left to find work in urban areas. (Photo by Kevin Frayer/Getty Images)

An injured woman is helped by emergency workers as she lies on the sidewalk in Times Square after a speeding vehicle struck pedestrians on the sidewalk in New York City, U.S., May 18, 2017. A car plowed into a crowd of pedestrians in New York' s bustling Times Square, leaving one person dead and at least 12 other injured in what officials said was an accident. (Photo by Mike Segar/Reuters)

The symbol for “One Orlando” is spelled out at a makeshift memorial at Lake Eola in downtown Orlando, Fla., Saturday, June 18, 2016. Nearby, visitors lit candles and prayed at a larger memorial, at the Dr. Phillips Center for the Performing Arts, to mourn the victims of the Pulse massacre. (Photo by Joe Burbank/Orlando Sentinel via AP Photo)

A participant dressed as a mermaid goes to swim in the beach after taking part in the Annual Mermaid Parade in Brooklyn, New York, June 18, 2016. The annual parade, founded in 1983, seeks to bring mythology to life for residents, create confidence in the district and to allow artistic self-expression in public, according to the parade's website. (Photo by Eduardo Munoz/Reuters)

Scientist Jiri Sindelar checks a ring of a Boreal owl chick outside the “Smart Nest Box”, which allows the study of birds by using mounted cameras, in a forest near the village of Mikulov, Czech Republic, June 18, 2016. (Photo by David W. Cerny/Reuters)