A migrant smokes a cigarette as he waits among others to cross the Croatian border near the village of Berkasovo, Serbia October 19, 2015. Thousands of migrants clamoured to enter European Union member Croatia from Serbia on Monday after a night spent in the cold and mud of no-man's land, their passage west slowed by a Slovenian effort to impose limits on the flow to western Europe. (Photo by Marko Djurica/Reuters)

Indonesian tourists take photos at the Marina Bay in Singapore May 14, 2015. When Singapore celebrated its 50th birthday as an independent country in August,the city state bore little resemblance to the tiny island nation that was expelled from Malaysia in 1965. Its physical stature has swollen by 20 percent thanks to one of the world's most aggressive land reclamation drives. (Photo by Edgar Su/Reuters)

A Turkana tribeswoman reacts after an accidental fire of a shelter in Turkana settlement in Ilemi Triangle, Kenya, July 15, 2019. The Ilemi Triangle, a disputed sliver of land along the border with Ethiopia and South Sudan, is the northernmost tip of Turkana, Kenya's poorest county. A series of deadly clashes between the Turkana community and other ethnic groups that they said had crossed from South Sudan have put people on edge, to the point of posting lookouts. (Photo by Goran Tomasevic/Reuters)

Brazilian natives of the Pareci tribe play head football with a hand-made ball for a demonstration, during the first day of the International Games of Indigenous Peoples, in Cuiaba, state of Mato Grosso, on November 10, 2013. 1500 natives from 49 Brazilian ethnic groups and from another 17 countries are gathering in Cuiaba until November 16 to compete in some 30 athletic disciplines, many of their own. (Photo by Christophe Simon/AFP Photo)

Israeli soldiers play the parts of wounded civilians during a drill simulating a toxic spill from an attack on a train in Beersheba, southern Israel, 13 January 2016, as Home Front medical teams, fire fighters and police carry out rescue operations. The large scale drill is the concluding exercise of the Fourth International Conference on Healthcare System Preparedness and Response to Emergencies and Disasters and includes some 200 of the world's experts on health system readiness from around the world. The conference is dealing with all types of medical emergencies from terrorist attacks to natural disasters. (Photo by Jim Hollander/EPA)

Members of an American landing party assist troops whose landing craft was sunk by enemy fire off Omaha beach, near Colleville sur Mer, France, June 6, 1944. REUTERS/Weintraub/US National Archives

U.S. Secretary of State John Kerry stands inside the historic Shackleton hut near McMurdo Station, Antarctica, Friday, November 11, 2016. Kerry became the highest-ranking American official to visit Antarctica when he landed for a two-day trip on Friday. He's been hearing from scientists about the impact of climate change on the frozen continent. Kerry's aides described the trip as a learning opportunity for the secretary of state. He has been receiving briefings from scientists working to understand the effects of climate change on Antarctica. Kerry has made climate change an intensive focus of American diplomacy during his term, and had previously spent decades working on the issue as a U.S. senator. Trump has called climate change a hoax and said he would “cancel” U.S. involvement in the landmark Paris Agreement on global warming. (Photo by Mark Ralston/Pool Photo via AP Photo)

A boy poses for a photo as he plays with a homemade toy gun in Qayara, south of Mosul, Iraq, Tuesday, November 22, 2016. For months, residents of the Iraqi town of Qayara have lived in the darkness from a cloud of toxic fumes released by oil fields lit by retreating Islamic State fighters. (Photo by Felipe Dana/AP Photo)