A farmer harvests tobacco leaves at a plantation in the valley of Vinales, in the western Cuban province of Pinar del Rio, January 27, 2015. (Photo by Pilar Olivares/Reuters)

A folk performer (front R) with make-up and props takes part in a “Blood Shehuo” parade, during a performance in Linyi county, Shanxi province March 21, 2015. “Shehuo” is the common name of Chinese traditional activities consisting of folk performances in northern China. The “Blood Shehuo” performers use make-up and props to re-enact scenes of horror in classic Chinese novels like Water Margin. (Photo by Reuters/Stringer)

A general view of dried-up rivers in the Pilbara region of Western Australia December 2, 2013. Western Australia's Pilbara region, which is the size of Spain, has the world's largest known deposits of iron ore and supplies nearly 45 percent of global trade in the mineral. (Photo by David Gray/Reuters)

Hungarian pilot and European champion Zoltan Veres flies under the oldest Hungarian bridge, the “Lanchid” (Chain Bridge) with his “MXS” type plane on May 1, 2014 during a Red Bull flying and car show around the Danube River of Budapest downtown. (Photo by Attila Kisbenedek/AFP Photo)

Mohammad, a 13-year-old fighter from the “Free Syrian Army”, plays with a cat in Aleppo's Bustan al-Basha district, Syria October 28, 2013. Mohammad joined the Free Syrian Army after his father died during clashes with the Syrian regime. The gun he is using was his father's. (Photo by Molhem Barakat/Reuters)

Framed by the setting sun, an American Bison grazes at the Tallgrass Prairie National Preserve on Tuesday, April 28, 2015, near Strong City, Kan. The buffalo herd at Tallgrass is one of the few herds of wild bison left in the United States. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

In this photo taken Tuesday, June 23, 2015, a Ukrainian serviceman from the Kiev-2 volunteer battalion fires an weapon at a frontline in the village of Krymske, east Ukraine. Few places along the front line in east Ukraine see regular fighting as bitter as the village of Krymske. For now, Krymske is in the hands of Ukrainian government forces and the volunteer battalions that fight alongside them. (Photo by Evgeniy Maloletka/AP Photo)

Paul, 9, dumps a bucket of water over his head at a fountain near government buildings during hot weather on July 1, 2015 in Berlin, Germany. Temperatures across northern Europe are rising and in Germany a high of 36 degrees is forecast for the weekend. (Photo by Sean Gallup/Getty Images)