Passengers travel on the London train and underground system during the Christmas party season, December 18, 2015. (Photo by Paul Hackett/Reuters)

An Iraqi woman attends a festival commemorating the International Day of Peace in Baghdad, September 21, 2015. (Photo by Thaier al-Sudani/Reuters)

A person dressed as a pumpkin monster poses at the premiere of the film “Goosebumps”, in Los Angeles, California October 4, 2015. (Photo by Danny Moloshok/Reuters)

Indonesian Presidential Security Forces (Paspampres) personnel show their skills during an anti terror exercise in Jakarta, Indonesia on 09 April 2015. The drill is in preparation for the 60th Asian-African Conference planned to be held in Jakarta from 21 to 23 April 2015. (Photo by Bagus Indahono/EPA)

A motorcyclist dodges in the annual water-splashing festival to mark the New Year of the Dai minority in Menglian, Yunnan province April 13, 2015. (Photo by Wong Campion/Reuters)

A worker refreshes himself with a fan after loading a container with rice bags at an export plant in the central Chainat province in Thailand, December 16, 2015. (Photo by Jorge Silva/Reuters)

An immigrant from Mali rests at the Greek-Macedonian border before an attempt to flee to Macedonia May 13, 2015 village of Idomeni in Kilkis prefecture May 13, 2015. Hundreds of mostly Afghan, Syrian, and African immigrants cross daily from Greece into Macedonia on their way to northern European countries; most of them are turned back by Macedonian border guards. (Photo by Yannis Behrakis/Reuters)

Visitors walk past a train-shaped ice sculpture ahead of the 31st Harbin International Ice and Snow Festival in the northern city of Harbin, Heilongjiang province, January 4, 2015. The winter festival will be officially opened on January 5, 2015. (Photo by Kim Kyung-Hoon/Reuters)