Bull riders prepare prior to a bull riding event in Santa Tecla, El Salvador, December 15, 2016. (Photo by Jose Cabezas/Reuters)

Women pose for a picture at the entrance of the Carlton Hotel, in the government controlled area of Aleppo, Syria December 17, 2016. (Photo by Omar Sanadiki/Reuters)

A reveller is photographed during a traditional Maracatu carnival in Olinda, Brazil February 8, 2016. (Photo by Ueslei Marcelino/Reuters)

Employees work on an electric train assembly line at the “Stadler Minsk” plant in Fanipol, Belarus February 10, 2016. (Photo by Vasily Fedosenko/Reuters)

A Saddle-billed Stork is seen in Amboseli National park, Kenya, February 10, 2016. (Photo by Goran Tomasevic/Reuters)

A fly rides a butterly, July 2016. (Photo by Petar Sabol Sharpeye/Rex Features/Shutterstock)

A man pushes her daughter on a cart as they shop at a market in Seoul, South Korea, July 26, 2016. (Photo by Kim Hong-Ji/Reuters)

Iraqi forces gather during an operation to attack Islamic State militants in Mosul, Iraq, October 21, 2016. (Photo by Reuters/Stringer)