Vultures gather to eat waste in Bica beach, on the banks of the Guanabara Bay, with the Sugar Loaf mountain in background, 500 days ahead the Rio 2016 Olympic Games in Rio de Janeiro March 24, 2015. As part of its Olympic bid, Rio promised to clean up 80 percent of the bay for the games. But local government officials have already admitted that a cleanup by 2016 is not achievable. Despite millions of dollars of investment over the years, the bay still stinks of sewage. Sailors who visited the city for test events complained of a floating sofa and a dead dog in the water. (Photo by Ricardo Moraes/Reuters)

A Zimbabwean subsistence farmer holds a stunted maize cob in his field outside Harare, January 20, 2016. About 14 million people face hunger in Southern Africa because of a drought that has been exacerbated by an El Nino weather pattern, the United Nations World Food Programme (WFP) said on Monday. In Zimbabwe, 1.5 million people, more than 10 percent of the population, face hunger, WFP said. (Photo by Philimon Bulawayo/Reuters)

A boy sits in a canoe in front of a shed built on a raft in the Makoko fishing community on the Lagos Lagoon, Nigeria February 29, 2016. In Makoko, a sprawling slum of Nigeria's megacity Lagos, a floating school capable of holding up to a hundred pupils has since November brought free education to the waterways known as the Venice of Lagos. It offers the chance of social mobility for youngsters who, like most of the city's 21 million inhabitants, lack a reliable electricity and water supply and whose water-based way of life is threatened by climate change as well as rapid urbanisation. (Photo by Akintunde Akinleye/Reuters)

Alfred Yetta (L) and Kay Manning pose for a photo in front of a cardboard cut-out of Pope Francis, during an event organised by Christa Scalies, the co-creator of the Pop-Up Pope, in Fado Irish Pub & Restaurant in Philadelphia, Pennsylvania, September 16, 2015. (Photo by Mark Makela/Reuters)

An Indonesian woman known as Linda (C) is helped by two Sharia officials after being caned for spending time in close proximity with a man who is not her husband, which is against Sharia law, in Banda Aceh on February 2, 2017. Aceh is the only province in the world's most populous Muslim-majority country that imposes sharia law. People can face floggings for a range of offences – from gambling, to drinking alcohol, to gay sеx. (Photo by Chaideer Mahyuddin/AFP Photo)

A member of Team Chez Victor falls in the water while competing during the Ice Canoe race at the Quebec Winter Carnival in Quebec City, February 5, 2017. (Photo by Mathieu Belanger/Reuters)

In this Monday, July 25, 2016 photo, skydiver Luke Aikins smiles as he jumps from a helicopter during his training in Simi Valley, Calif. After months of training, this elite skydiver says he's ready to leave his chute in the plane when he bails out 25,000 feet above Simi Valley on Saturday. That's right, no parachute, no wingsuit and no fellow skydiver with an extra one to hand him in mid-air. (Photo by Jae C. Hong/AP Photo)

In a July 14, 1967 file photo, left, National Guardsmen make their way along Market Street in Newark, N.J, after an evening of deadly rioting and looting in what came to be known as the Newark riots. In a June 16, 2017 photo, right, an ambulance drives on the same block 50 years later. (Photo by AP Photo/File, left; Julio Cortez, right)