A Syrian boy receives treatment at a hospital in the regime-held part of Aleppo on October 13, 2016. Syrian state television said four children were killed by rebel rocket fire on a school in a western regime-held neighbourhood. (Photo by George Ourfalian/AFP Photo)

Models present creations during the Monse and Oscar de la Renta Autumn/Winter 2017 collection during New York Fashion Week in the Manhattan borough of New York, U.S., February 13, 2017. (Photo by Brendan McDermid/Reuters)

Indian Students of Rabindra Bharati University at the BT Road Campuses Celebrates the Holi, Color Festival on March 09, 2017 in Kolkata.Holi, the popular Hindu spring festival of colours is observed in India at the end of the winter season on the last full moon of the lunar month, and will be celebrated on March 13 this year. (Photo by Debajyoti Chakraborty/NurPhoto)

A grizzly bear eats a frozen fruits during a hot summer day at Rio de Janeiro's zoo January 13, 2015. According to a local climate institute, temperatures in Rio de Janeiro on Tuesday rose up to 34 degrees Celsius (93.2 degrees Fahrenheit). (Photo by Sergio Moraes/Reuters)

Students feed fruit to an elephant during Thailand's National Elephant Day in the ancient Thai capital Ayutthaya March 13, 2015. Thais honoured the elephant on Friday with special fruits and Buddhist ceremonies across the country to pay homage to their national animal. (Photo by Athit Perawongmetha/Reuters)

A Common Blue Morpho butterfly lands on the arm of Garbiella as it and hundreds of other butterflies from around the world fill the bird aviary for the next month at the San Diego Zoo Safari Park in San Diego, California March 13, 2015. Called the Butterfly Jungle, the exhibit has over 30 species of butterflies. (Photo by Mike Blake/Reuters)

Bulgarian Roma women from the close-knit Kalaidjii clan attend a so-called “bride fair” in a suburb of the city of Plovdiv April 13, 2015. Each year Roma families from the close-knit Kalaidjii clan gather during what they call a “bride fair”, an event offering parents a chance to meet and to arrange marriages for their children. (Photo by Stoyan Nenov/Reuters)

Storm clouds blanket the sky over Great American Ball Park as Starlin Castro #13 of the Chicago Cubs fields a ground ball in the fifth inning against the Cincinnati Reds as on July 7, 2014 in Cincinnati, Ohio. (Photo by Jamie Sabau/Getty Images)