Sami people from the Vilhelmina Norra Sameby, gather their reindeers herd in a corral for selection and calf labelling on October 27, 2016 near the village of Dikanaess, about 800 kilometers north-west of the capital Sweden. Sweden's Sami reindeer herders have more than hungry predators to worry about in the cold night, as the indigenous minority moves its flock to the winter pasture in the Nordic tundra. (Photo by Jonathan Nackstrand/AFP Photo)

A Colombian air force helicopter retrieves the bodies of victims from the wreckage of a plane that crashed into the Colombian jungle with Brazilian soccer team Chapecoense onboard near Medellin, Colombia, November 29, 2016. The chartered plane was carrying a Brazilian soccer team to the biggest match of its history when it crashed into a Colombian hillside and broke into pieces, killing 75 people and leaving six survivors, Colombian officials said Tuesday. (Photo by Jaime Saldarriaga/Reuters)

Iraqi Shiite fighters from the Hashed al- Shaabi (Popular Mobilisation) paramilitaries hold a position near the village of Tal Abtah, south of Tal Afar, on November 30, 2016, during a broad offencive by Iraq forces to retake the city Mosul from Islamic State group jihadists. (Photo by Ahmad Al- Rubaye/AFP Photo)

Sap runs out of a frankincense tree near Mader Moge, Somaliland, a breakaway region of Somalia on August 4, 2016In a tradition dating to Biblical times, men rise at dawn in the rugged Cal Madow mountains of Somaliland in the Horn of Africa to scale rocky outcrops in search of the prized sap of wild frankincense trees. (Photo by Jason Patinkin/AP Photo)

People are seen watching hot air balloons fly overhead during a two-day international hot air balloon festival in Eshkol Park near the southern city of Netivot, Israel July 22, 2016. (Photo by Amir Cohen/Reuters)

Tourists from the Middle East take pictures at Vrelo Bosne nature park in Ilidza near Sarajevo, Bosnia and Herzegovina, August 19, 2016. They discovered mountainous Bosnia, where half the population is Muslim, after the Arab Spring which destabilized many traditional holiday destinations such as Libya, Tunisia and Egypt. (Photo by Dado Ruvic/Reuters)

Migrants prepare their food outside shelters in a muddy field called the Grande-Synthe jungle, near Dunkirk, northern France, January 12, 2016. The Grande-Synthe jungle is a camp of tents and makeshift shelters where migrants and asylum seekers from Irak, Kurdistan and Syria gather. (Photo by Benoit Tessier/Reuters)

People climb on an artificial ice-wall in Liberec, about 100 km north of Prague, Czech Republic, Saturday, January 23, 2015. The wall was prepared in a former quarry just near the centre of the city. (Photo by Radek Petrasek/CTK via AP Photo)