Children attend a swim training session at Hangzhou Chen Jinglun Sport school Natatorium, where Chinese Olympic swimmer Sun Yang and Fu Yuanhui also trained, in Hangzhou, Zhejiang province, China, August 10, 2016. (Photo by Aly Song/Reuters)

Aisha, 15, (L) (who asked to withhold her last name), a Syrian refugee from Raqqa, waits with a fellow refugee while harvesting cannabis in the Bekaa valley, Lebanon October 19, 2015. Syrian refugees work to harvest and process spiky-leafed cannabis plants in neighbouring Lebanon’s Bekaa Valley. Often farmers of cotton and wheat back home in Raqqa province – now the de facto capital of Islamic State – the conflict in Syria drove them to seek safety in a region where Syrian migrant workers used to spend a few months a year before returning home. (Photo by Alia Haju/Reuters)

Films that are being screened are advertised in a makeshift cinema located under a bridge in the old quarters of Delhi, India May 25, 2016. A makeshift cinema hall under a 140-year-old bridge in the Indian capital is allowing poor rickshaw pullers and migrant labourers to escape daily hardship and sweltering heat into a world of Bollywood song, dance and romance. With the rusty iron floor of the bridge as its ceiling and some old rags acquired on the cheap from a nearby crematorium serving as curtains and floor mats, the cinema shows four films a day. (Photo by Cathal McNaughton/Reuters)

The Pied Piper of Hamelin, actually city tourism employee Michael Boyer, leads local children dressed as rats through a quiet street on November 19, 2012 in Hameln, Germany. The Pied Piper (in German: Der Rattenfaenger), is one of the many stories featured in the collection of fairy tales collected by the Grimm brothers, and the 200th anniversary of the first publication of the stories will take place this coming December 20th. Boyer, a U.S. citizen who has lived in Hameln for 15 years, and city children regularly perform a reenactment of the Pied Piper tale throughout the summer months. The Grimm brothers collected their stories from oral traditions in the region between Frankfurt and Bremen in the early 19th century, and the works include such global classics as Sleeping Beauty, Little Red Riding Hood, Rapunzel, Cinderella and Hansel and Gretel. (Photo by Sean Gallup)

A group of children and their dog playing an Easter game in Cardiff. The game involves trying to eat an Easter egg off a piece of string without using their hands. (Photo by Richards/Fox Photos/Getty Images). 26th March 1937

From the waters edge a New York policeman urges two young children to put their bathing costumes back on. (Photo by Ed Clarity/Keystone/Getty Images). July 1949

Tom Wilder, 17 from Kent, dives in the mud at the Glastonbury Festival site at Worthy Farm, Pilton on June 23, 2011 in Glastonbury, England. Music fans had to brave more rain today at the five-day festival which opened yesterday. This year the festival will feature headline acts U2, Coldplay and Beyonce. The festival, which started in 1970 when several hundred hippies paid 1 GBP to watch Marc Bolan, has grown into Europe's largest music festival attracting more than 175,000 people over five days. (Photo by Matt Cardy/Getty Images)

People use snowshoes during a tour of the Great Kemeri Bog, Latvia, October 17, 2015. The Kemeri bog is more than 8,000 years old and is one of the largest dry moss swamps in the Baltics. A more than decade-long joint restoration of the bog by the European Union and the Latvian government helped the bog recover its high moss marshes, damp black alder forests, floodplain meadows and seaside lakes – features now considered rare in Europe due to industrialisation. (Photo by Ints Kalnins/Reuters)