Ukrainian Air Force officers attend a graduation ceremony at the National University of Defence of Ukraine in Kiev, April 24, 2015. (Photo by Gleb Garanich/Reuters)
A participant smiles at the annual Christopher Street Day parade on Kurfuerstendamm in Berlin, Germany, June 27, 2015. (Photo by Fabrizio Bensch/Reuters)
A cloud of black smoke billows out the exhaust pipe of John Robertson's diesel dragster as he runs down the track during the 2015 NHRA Kansas Nationals, Friday, May 22, 2015, at Heartland Park in Topeka, Kan. (Photo by Chris Neal/The Topeka Capital-Journal via AP Photo)
A man poses for a pictures, as he transport logs on his bull-cart to make charcoal at La Campanera village, Nicaragua, May 22, 2015. Around 300 families live off the sale of charcoal in this area located in the dry corridor of Nicaragua. Friday marks World Environment Day. Picture taken May 22, 2015. REUTERS/Oswaldo Rivas