Convention goers dressed as bright colored Wookiees, a fictional species from the US epic space opera franchise Star Wars, prepare for a group photo outside the Comic Con 2016 in San Diego, California, USA, 22 July 2016. The San Diego Comic Con 2016 runs from 21 until 24 July. (Photo by David Maung/EPA)

An undated handout image provided by UNICEF Germany on 20 December 2016 shows the “UNICEF Photo of the Year 2016” by Iranian freelance photographer Arez Ghaderi. Ghaderi won the first prize for his picture of a girl in a makeshift tent city in the Razavi Khorasan province, Iran, it was announced at a ceremony in Berlin, Germany on 20 December 2016. (Photo by Ariz Ghaderi/EPA/UNICEF Deutschland)

Revellers attend the Play Time 2016 music festival on the outskirts of Ulaanbaatar, Mongolia, June 26, 2016. (Photo by Jason Lee/Reuters)

A barn painted with the U.S. flag is seen in the snow covered field in Kanawha, Iowa, United States, January 16, 2016. Iowa will be the first state to hold its primary, with both Democratic and Republican events being held February 1, 2016. (Photo by Jim Young/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 boy jumps over a puddle of water on the outskirts of Havana, Cuba March 21, 2016. (Photo by Ueslei Marcelino/Reuters)