Partially demolished houses stand in the Vila Autodromo slum with the Rio 2016 Olympic Park in the background in Rio de Janeiro, Brazil, February 25, 2016. (Photo by Ricardo Moraes/Reuters)

A visitor looks at pictures of French photographer Jacques-Henri Lartigue (1894-1986), on July 1, 2013 during the 44thd annual Rencontres d'Arles photography festival in Arles, southern France. The event runs until September 22. (Photo by Boris Horvat/AFP Photo)

A man stands at a passenger train damaged in a collision with a freight train in Moscow region May 20, 2014. The passenger train on its way to Moldova collided with a freight train near Moscow on Tuesday, killing at least four people and injuring 15, a spokeswoman for Russia's Emergencies Ministry said. The reason for the collision, near the town of Naro-Fominsk 55 km (34 miles) southwest of Moscow, was not immediately clear. (Photo by Grigory Dukor/Reuters)

An Anti-Balaka fighter, member of a militia opposed to the Seleka rebel group, puts a knife to his throat showing what he would do to any Seleka, on the outskirts of the Boy-Rabe neighborhood in Bangui on December 14, 2013. France raised alarm on December 13 over worsening violence in the Central African Republic, as UN chief Ban Ki-moon urged warring Christians and Muslims to stop the bloodshed that has left more than 600 dead in the past week. (Photo by Ivan Lieman/AFP Photo)

Private Wallace Tratford arrives home on leave, Drouin, Victoria, ca. 1944. A.I.F. Private Wallace Tratford, son of 1st Constable James Tratford, Drouin's only policeman (responsible for area of 105 square miles; 3,000 people), arrives home on his first leave from New Guinea battlefronts since he was married.

A caterpillar driven ferry with a 24 horsepower engine takes holidaymakers from the mainland at Bigbury in Devon to Burgh Island, a quarter of a mile away. (Photo by Reg Speller/Fox Photos/Getty Images). 4th April 1935

Elementary school children play outside their classrooms as mount Sinabung volcano spews thick volcanic ash in the background on February 10, 2017 in Karo, Indonesia. Mount Sinabung is one of the most active volcanoes in Indonesia and last erupted in May 2016, killing seven people. (Photo by Albert Damanik/Barcroft Images)

Figures of Francois Fillon (L), former French prime minister, member of The Republicans political party and 2017 presidential candidate of the French centre-right, and French National Front leader Marine Le Pen are paraded through the crowd during the 133rd Carnival parade, the first major event since the city was attacked during Bastille Day celebrations last year in Nice, France, February 11, 2017. (Photo by Eric Gaillard/Reuters)