A woman rides a custom bike during "Bike Kill 12" in the Brooklyn borough of New York City, October 31, 2015. "Bike Kill" is an annual gathering of builders and riders of home-made bicycles that culminates in a tall bike jousting competition. (Photo by Stephanie Keith/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)

Tourists watch the sunrise and pray outside a church on the summit of Mount Moses, near the city of Saint Catherine, in the Sinai Peninsula, south of Egypt, December 9, 2015. (Photo by Amr Abdallah Dalsh/Reuters)

Anti-balaka militia originally sprang up to protect the Christian population of the Central African Republic, but now stand accused of human rights abuses themselves. Last month, the African Union branded militia targeting Muslims in Central African Republic as “terrorists” and said they would be treated as enemy combatants, a day after killing a Congolese peacekeeper and amid deepening international frustration at continuing violence in the impoverished and landlocked country. Photo: A female member of the anti-balaka, a Christian militia, patrols with other militiamen outside village of Zawa April 8, 2014. (Photo by Goran Tomasevic/Reuters)

A bull rams inmates seated at a card table in the Convict Poker event at the Angola Prison Rodeo in Angola, La., Saturday, April 26, 2014. Those competing in the rodeo have to pass a physical to be deemed strong and healthy enough, and thousands of others work year-round making arts and crafts to sell at the event, according to the prison's athletic director. (Photo by Gerald Herbert/AP Photo)

North Korean girls in similar bathing suits stand under a shower at the Songdowon International Children's Camp, Tuesday, July 29, 2014, in Wonsan, North Korea. The camp, which has been operating for nearly 30 years, was originally intended mainly to deepen relations with friendly countries in the Communist or non-aligned world. But officials say they are willing to accept youth from anywhere – even the United States. (Photo by Wong Maye-E/AP Photo)

A dog rides a wave while competing during the 5th Annual Surf Dog competition at Huntington Beach, California, on September 29, 2013. (Photo by Frederic J. Brown/AFP Photo)

A woman struggles with an umbrella in the wind and rain while walking in Derby city centre, on December 23, 2013. (Photo by Rui Vieira/PA Wire)