Kurdish pesh merga troops fire at Islamic State positions as they move toward the Iraqi town of Badana Pichwk on Monday morning, October 17, 2016. Kurdish forces began Monday advancing on a string of villages east of Mosul, the start of a long-awaited campaign to reclaim Iraq's second-largest city from the Islamic State, which seized it more than two years ago, officials said. (Photo by Bryan Denton/The New York Times)

A mahout leads an elephant calf to the river Tunga for bathing at the Sakrebailu Elephant Camp in Sakrebailu in the southern state of Karnataka, India, November 12, 2016. (Photo by Abhishek N. Chinnappa/Reuters)

A man dressed as the Sesame Street character Big Bird sits on a bench waiting to take pictures with people walking through Central Park in New York U.S., November 14, 2016. (Photo by Shannon Stapleton/Reuters)

Men help a woman affected by tear gas used by National Police officers to disperse a demonstration of supporters of Fanmi Lavalas political party in the streets of Port-au-Prince, Haiti, November 22, 2016. (Photo by Andres Martinez Casares/Reuters)

A woman paints the floor of a pond as her child pulls at her saree in Delhi, India November 23, 2016. (Photo by Cathal McNaughton/Reuters)

Trucks loaded with tree trunks are burned by agents of the Brazilian Institute for the Environment and Renewable Natural Resources, or Ibama, during an operation to combat illegal mining and logging, in the municipality of Novo Progresso, Para State, northern Brazil, November 11, 2016. When able to do their job, agents of the Brazilian Institute for the Environment and Renewable Natural Resources, or Ibama, are decisive, punishing illegal loggers on the spot. Nearly twice the size of India, the Amazon absorbs an estimated 2 billion tonnes of carbon dioxide per year, making its preservation vital in the fight to halt global warming. (Photo by Ueslei Marcelino/Reuters)

A street actor dressed as a devil frightens children in downtown Prague in Prague, Czech Republic, Monday, December 5, 2016. On the eve of St. Nicholas, Czechs traditionally celebrate by dressing up as Devils, Angels and St. Nicholas, and visiting children in their homes handing out small presents, coal, potatoes or other gifts. (Photo by Petr David Josek/AP Photo)

An airplane is silhouetted at sunrise, seen from the suburb of Saint-Cloud, near Paris, France, 08 December 2016. Paris is undergoing a third day pollution spike, prompting the city to limit vehicle circulation. (Photo by Ian Langsdon/EPA)