An injured boy who is undergoing surgery, after he was injured in what activists said was an airstrike by forces loyal to Syria's president Bashar al-Assad, rests inside a field hospital in the Douma neighborhood of Damascus, Syria December 5, 2015. Douma in Syria, an area controlled by rebels fighting to topple President Bashar al-Assad, has been shelled continuously for the past three years. The injured are taken to basements and shelters transformed into field hospitals run by medical staff who have stayed in the battered neighbourhood of Damascus. (Photo by Bassam Khabieh/Reuters)

A festival goer uses a hula hoop, as revelers gather ahead of this weekends Glastonbury Festival of Music and Performing Arts on Worthy Farm in Somerset, southwest England, on June 25, 2014. US metal giants Metallica will play this year's coveted Saturday night headline spot at Britain's Glastonbury festival, organisers announced Thursday. It will be the “Master of Puppets” four-piece's first appearance at the legendary festival, held in south west England, following on from The Rolling Stones' Worthy Farm debut last year. (Photo by Leon Neal/AFP Photo)

An excavator removes a dead bear at the zoo in Tbilisi, Georgia, June 17, 2015. Tigers, lions, bears and wolves were among more than 30 animals that escaped from a Georgian zoo and onto the streets of the capital Tbilisi on Sunday during floods that killed at least 12 people. REUTERS/David Mdzinarishvili

A woman holds her umbrella while walking against strong winds as Typhoon Soudelor approaches Taiwan in Taipei, August 7, 2015. Taiwan evacuated hundreds of people from their homes on Friday as the strongest typhoon to threaten the island in two years churned towards it and was expected to make landfall early on Saturday. (Photo by Pichi Chuang/Reuters)

A man holds up for a picture a one hundred trillion Zimbabwean dollars note inside a shop in Harare, Zimbawe, June 12, 2015. Hyperinflation in Zimbabwe was a period of currency instability that began in the late 1990s shortly after the confiscation of private farms from landowners, towards the end of Zimbabwean involvement in the Second Congo War. During the height of inflation from 2008 to 2009, it was difficult to measure Zimbabwe's hyperinflation because the government of Zimbabwe stopped filing official inflation statistics. However, Zimbabwe's peak month of inflation is estimated at 79.6 billion percent in mid-November 2008. (Photo by Philimon Bulawayo/Reuters)

People out in Aberystwyth on “Booze Black Friday” or “Mad Friday” in Aberystwyth, Wales, UK on December 16, 2016. The “Booze Black Friday” is the last working Friday before Christmas when workers celebrate with their colleagues. Alcohol sales in pubs, clubs and off-licences rise dramatically on this day. (Photo by Keith Morris/Alamy Live News)

Festival goers participate in a dance class on embracing kinetic intimacy in the dance shala a the Oregon Eclipse Festival, August 20, 2017, at Big Summit Prairie ranch in Oregon' s Ochoco National Forest near the city of Mitchell ahead of the total solar eclipse on August 21, 2017. (Photo by Robyn Beck/AFP Photo)

Afghan policemen take position at the site of a suicide attack followed by a clash between Afghan forces and insurgents after an attack on a Shi'ite Muslim mosque in Kabul, Afghanistan on Friday, August 25, 2017. Gunmen stormed a Shiite mosque in the Afghan capital while worshippers were at Friday prayers, setting off an explosion that killed a security guard outside and pushing into the shrine, officials said. (Photo by Omar Sobhani/Reuters)