Revellers celebrate New Year's Day in central Moscow, Russia, January 1, 2016. (Photo by Tatyana Makeyeva/Reuters)

Internally displaced Syrian children play inside a refugee camp in the Hama countryside, Syria January 1, 2016. (Photo by Ammar Abdullah/Reuters)

Participants take part in a New Year's Jump into the Sea in Portoroz , Slovenia, January 1, 2016. (Photo by Srdjan Zivulovic/Reuters)

An enthusiast dressed as a zombie takes part in the annual Zombie Walk festival in Prague June 1, 2013. (Photo by David W. Cerny/Reuters)

Artists perform during the opening show directed by German director Volker Hesse, on the opening day of the Gotthard rail tunnel, at the fairground Rynaecht at the northern portal in Erstfeld, Switzerland, Wednesday, June 1, 2016. The construction of the 57 kilometer long tunnel began in 1999, the breakthrough was in 2010. After the official opening on June 1, the commercial operation will start in December 2016. (Photo by Ruben Sprich\Pool Photo via AP Photo)

Edibles are displayed at Shango Cannabis shop on first day of legal recreational marijuana sales beginning at midnight in Portland, Oregon October 1, 2015. The sale of marijuana for recreational use began in Oregon on October 1, 2015 as it joined Washington state and Colorado in allowing the sale of a drug that remains illegal under U.S. federal law. (Photo by Steve Dipaola/Reuters)

Deers walk past Indonesia's honour guard as they wait for the arrival of Saudi Arabia's King Salman bin Abdul Aziz at the presidential palace in Bogor on March 1, 2017. Cheering crowds welcomed King Salman on March 1 as he began the first visit by a Saudi monarch to Indonesia for almost 50 years, seeking stronger economic ties with the world's most populous Muslim-majority country. (Photo by Adek Berry/AFP Photo)