Fighters of the Popular Resistance Committees stand during a graduation ceremony of the affiliate special forces of the Popular Resistance, in Yemen's southwestern city of Taiz October 8, 2015. (Photo by Reuters/Stringer)

Devotees of the Chinese Jui Tui shrine are seen with spikes piercing their cheeks during a procession celebrating the annual vegetarian festival in Phuket, Thailand in this October 19, 2015 combination photo. The festival, featuring face-piercing, sacrifice, spirit mediums and strict vegetarianism celebrates the local Chinese community's belief that abstinence from meat and various stimulants during the ninth lunar month of the Chinese calendar will help them obtain good health and peace of mind. (Photo by Jorge Silva/Reuters)

A man flies a kite on the Bund while buildings of Pudong's Lujiazui financial district stand across the Huangpu River as the sun rises in Shanghai, China, on Friday, October 2, 2015. (Photo by Qilai Shen/Bloomberg)

A street vendor warms his foot around a fire during cold weather in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria, January 4, 2016. (Photo by Khalil Ashawi/Reuters)

Revellers take a break during the Carnival 2016 parade in Port-au-Prince, Haiti, February 8, 2016. (Photo by Andres Martinez Casares/Reuters)

A migrant labourer brushes his teeth in front of a scrapped helicopter model in Mumbai, India, April 13, 2016. (Photo by Danish Siddiqui/Reuters)

MMVA host model Gigi Hadid takes pictures with fans as she arrives for the iHeartRadio Much Music Video Awards (MMVAs) in Toronto, Ontario, Canada June 19, 2016. (Photo by Peter Power/Reuters)

Visitors look up at mock-ups of dinosaur skeletons inside the Museum of Natural History in Pyongyang on September 28, 2016. (Photo by Ed Jones/AFP Photo)