First graders attend a festive ceremony to mark the start of another school year in Slaviansk, September 1, 2014. September 1 marks the start of a new academic year for students in Ukraine. (Photo by Gleb Garanich/Reuters)

Model Juliana Paesthe (C) of Viradouro samba school participates in the annual carnival parade in Rio de Janeiro's Sambadrome, February 15, 2015. (Photo by Ricardo Moraes/Reuters)

Chinese artist Zhou Jie takes a nap on an unfinished iron wire bed, one of her sculpture works, after lunch at Beijing Now Art Gallery, in Beijing August 11, 2014. Zhou started her art project titled “36 Days” on August 9, in which she would live inside an exhibition hall with an unfinished iron wire bed, some iron wire sculptures in the shape of stuffed animal dolls, a certain amount of food and her mobile phone, for 36 days. The entire process is open to visitors and she may also interact with them, according to Zhou. (Photo by Jason Lee/Reuters)

Breitling Wingwalker Freya Paterson, from Liverpool, UK, flies above Kuwait City's iconic Water Towers with pilots David Barrell and Martyn Carrington, on March 6, 2014. The team loop and roll up to 160 mph enduring G-forces of 4-5g. Crowds are expected to line the Kuwaiti coastline to catch a glimpse of the Wingwalking team on Saturday, March 8, 2014, to mark the opening of the first dedicated boutique in the city for the prestigious watch brand. (Photo by Katsuhiko Tokunaga/Breitling)

Stranded cars remain in a flooded street during an intense rainstorm in Havana, on April 29, 2015. Two people were killed, three buildings collapsed and another 24 suffered some kind of damage due to the heavy rain that affected several sectors of Havana Wednesday. (Photo by Yamil Lage/AFP Photo)

Participants prepare backstage before the 5th “Strongo Cup” open amateur bodybuilding tournament at the State Opera and Ballet Theatre in Russia's Siberian city of Krasnoyarsk, November 1, 2014. Participants from all over Russia took part in the tournament competing in bodybuilding, body fitness and bikini fitness disciplines. (Photo by Ilya Naymushin/Reuters)