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)

A man watches the huge waves which brakes at the Paseo Nuevo's promenade in San Sebastian, Basque Country, Spain on 11 January 2016 where the wind has reached to 90 km/h and have been registred waves of eight kilometres due to the bad weather. (Photo by Juan Herrero/EPA)

Alicia Vargas, 23, a performer from the Urus Diablada group, tied the laces of her boots before a practice ahead of Carnival in Oruro, Bolivia February 5, 2016. (Photo by David Mercado/Reuters)

A 20 metre high spiral staircase in a tower used as an emergency exit, is seen inside a Federal Reserve bank (Bundesbank) bunker, prior to the bunker's official opening to the public in Cochem, Germany, March 18, 2016. West Germany's Central Bank (Deutsche Bundesbank) stored some 20 billion German marks of emergency notes in two underground bunkers, one in Frankfurt the other in Cochem, between 1964-1988 during the cold war. (Photo by Kai Pfaffenbach/Reuters)

In this Thursday, March 17, 2016 photo, 33-year-old Palestinian clown doctor Alaa Miqdad, left, entertains 3-year-old patient Yaqin Shawaf, who suffers from dialysis, in the department of kidney diseases at Al-Rantisi children's hospital in Gaza City. (Photo by Adel Hana/AP Photo)

Soccer is played on a television mounted in a workshop in the Willets Point area of Queens in New York October 27, 2015. Willets Point, also known as the Iron Triangle, is an industrial precinct that sits in the shadow of Citi Field, home of the New York Mets baseball team. Many businesses within Willets Point employ a largely immigrant workforce. (Photo by Andrew Kelly/Reuters)

In this Wednesday, July 20, 2016 photo, a child carries kettles through a flooded street with a woman in Tianjin, China. China says dozens of people have died or gone missing since Monday in massive floods across the country's north. (Photo by Chinatopix via AP Photo)

Two boys look out from the Mangueira slum towards the Maracana Stadium that is hosting the Rio's 2016 Summer Olympics opening ceremonies, in Rio de Janeiro, Brazil, Friday, August 5, 2016. (Photo by Leo Correa/AP Photo)