Protesters wear masks, the left in the colors of the Kenyan national flag, as they join others carrying mock coffins and red-painted crosses, symbolizing the blood of the 28 non-Muslims singled out and killed in the recent attack on a bus in Mandera by Somali militant group al-Shabab, outside government offices in downtown Nairobi, Kenya Tuesday, November 25, 2014. (Photo by Ben Curtis/AP Photo)

Law enforcement officers stand, with some turning their backs, as New York City Mayor Bill de Blasio speaks on a monitor outside the funeral for NYPD officer Wenjian Liu in the Brooklyn borough of New York January 4, 2015. Tens of thousands of law enforcement officers from across the country gathered on Sunday for the funeral of the second of two New York City policemen killed last month in an ambush that galvanized critics of Mayor de Blasio. (Photo by Shannon Stapleton/Reuters)

Chief priest Gbenga Saala raises a cutlass to kill a dog during an annual prayer and sacrifice celebration of the iron god Ogun in Abuja, Nigeria, June 23, 2015. Every year worshippers offer a dog as sacrifice to Ogun, a traditional Nigerian deity, in hope of an auspicious year ahead. Taxi drivers, blacksmiths, panel beaters and mechanics – trades that depend on metal for their livelihood – pay homage to Ogun, led by high priest Gbenga Saala. As part of the ceremony, the priest pours the dog’s blood on symbols of these workers’ trade: keys, spanners and other tools piled up in a metal barrel. (Photo by Afolabi Sotunde/Reuters)

Men cover their heads from the sun while riding on a motorcycle during a hot day in Cairo, Egypt, August 17, 2015. A heatwave killed at least 61 people across Egypt from Sunday to Tuesday and caused nearly 600 people to be admitted to hospital, Egypt's health ministry said on state news agency MENA on Wednesday. (Photo by Amr Abdallah Dalsh/Reuters)

People pass by a vehicle almost completely submerged on a street covered with mud due to heavy floods in Tekija village September 17, 2014. One person died in Serbia and authorities scrambled to evacuate hundreds of people from villages threatened by rising rivers, officials said on Tuesday, in scenes recalling the devastating May flooding that killed dozens. (Photo by Djordje Kojadinovic/Reuters)

A demonstrator throw a firebomb during clashes with Turkish riot police officers in Istanbul, Turkey, Friday, May 1, 2015. The government assigned 30,000 police officers backed by helicopters as workers and demonstrators determined to defy a government ban, tried to march to iconic Taksim Square, where 35 people were killed during May Day celebration in 1977. (Photo by Emrah Gurel/AP Photo)

Members of the media film as a ranger performs a post mortem on the carcass of a rhino after it was killed for its horn by poachers at the Kruger national park in Mpumalanga province August 27, 2014. Rhino poachers in South Africa now risk giving themselves away when they shoot thanks to a high-tech, gunfire-detection system being piloted in the country's flagship Kruger National Park. The stakes are high, for rhinos are being slain in escalating numbers for their prized horns, alarming both conservationists and the government since wildlife in South Africa is an important tourist draw. (Photo by Siphiwe Sibeko/Reuters)

Photo taken on November 5, 2015 shows flood in Bento Rodrigues, a town in the southeastern Brazilian state of Minas Gerais, after a dam at a mining waste site burst early Thursday. An iron ore tailings dam in the southeast Brazilian state of Minas Gerais collapsed Thursday, killing at least 15 people, according to local media reports. (Photo by Agencia Estado/Xinhua Press/Corbis)