A girl wearing a butterfly headband poses for a picture near damaged buildings in the rebel held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria January 19, 2017. (Photo by Bassam Khabieh/Reuters)

A participant covered in coloured powder gestures as she stands near a Syrian army soldier during “I Love Damascus” marathon at Umayyad Square in Damascus, Syria October 7, 2016. (Photo by Omar Sanadiki/Reuters)

A participant in costume poses to a camera after a Halloween parade in Kawasaki, south of Tokyo, Japan October 30, 2016. More than 130,000 spectators turned up to watch the parade, where about 2,600 participants dressed up in costumes, according to the organiser. ((Photo by Kim Kyung-Hoon/Reuters)

The 2016 Greenwich Village Halloween parade, October 31, 2016 in the Manhattan borough of New York City. (Photo by Anthony Causi)

A person dressed as Republican presidential nominee Donald Trump participates in the Greenwich Village Halloween Parade in Manhattan, New York, U.S., October 31, 2016. (Photo by Andrew Kelly/Reuters)

A man reacts over dead bodies prior to burial in a graveyard after shelling in the rebel held besieged town of Douma, eastern Ghouta in Damascus, Syria, October 24, 2016. (Photo by Bassam Khabieh/Reuters)

A man covered with dust sits on a street following a reported air strike by Syrian government forces in the rebel-held neighbourhood of Sukkari in the northern city of Aleppo on May 30, 2016. (Photo by Baraa Al-Halabi/AFP Photo)

This Wednesday, August 31, 2016 photo, provided by the Syrian anti-government activist group Aleppo Media Center (AMC), shows Syrian boys dive into a hole filled with water that was caused by a missile attack in the rebel-held neighborhood of Sheikh Saeed in Aleppo province, Syria. (Photo by Aleppo Media Center via AP Photo)