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)

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)

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)

A cat receives acupuncture treatment in Shanghai, China on August 21, 2017. Traditional practitioners believe acupuncture of the body can stimulate blood circulation to promote healing and relieve some aches and pains. (Photo by Aly Song/Reuters)

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 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)

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 woman jumps into water from the roof of Murru prison, an abandoned Soviet prison, in Rummu quarry, Estonia, during hot weather July 4, 2015. During the Soviet time, Rummu quarry was used as a mining site for Vasalemma marble and most of the workforce came from among the detainees of Murru prison. When the prison closed after 1991, pumps that once kept the quarry and the prison dry were shut down, causing water to fill the quarry. It has become an unofficial and unguarded swimming and diving spot, attracting locals and tourists. (Photo by Ints Kalnins/Reuters)