Women in costumes walk as they participate in Halloween celebrations in the downtown of Seoul, South Korea, October 31, 2015. (Photo by Kim Hong-Ji/Reuters)

Tourists walk above a tea plantation in Enshi, Hubei province, December 27, 2015. (Photo by Reuters/Stringer)

A couple who did not give their names walk in downtown Havana, February 2, 2015. (Photo by Alexandre Meneghini/Reuters)

People are reflected in a shop window as they walk along a street in a shopping district in Tokyo, Japan June 25, 2015. (Photo by Thomas Peter/Reuters)

People are reflected in mirrors as they walk in a busy shopping district in Tokyo, Japan, December 25, 2015. (Photo by Thomas Peter/Reuters)

People walk along a street with long-tailed macaques in Lopburi, north of Bangkok November 29, 2015. (Photo by Jorge Silva/Reuters)

Attendees at Wizard World Comic Con walk through hallways in Chicago, Illinois, United States, August 22, 2015. (Photo by Jim Young/Reuters)