This file photo provided on Sunday February 15, 2015 by the Syrian anti-government activist group Aleppo Media Center (AMC), which has been authenticated based on its contents and other AP reporting, shows Syrian rebels firing locally made shells against the Syrian government forces, in Aleppo, Syria. (Photo by AP Photo/Aleppo Media Center)

Police officers with a sniffer dog check a railway as the Soyuz MS spacecraft for the next International Space Station (ISS) crew of Kate Rubins of the U.S., Anatoly Ivanishin of Russia and Takuya Onishi of Japan is ready to be transported from an assembling hangar to the launchpad ahead of its launch scheduled on July 7, at the Baikonur cosmodrome in Kazakhstan July 4, 2016. (Photo by Shamil Zhumatov/Reuters)

Afghan children play soccer in front of the war-damaged Darul Aman Palace in the suburbs of Kabul, Afghanistan, Wednesday, June 8, 2011. (Photo by Gemunu Amarasinghe/AP Photo)

Britain Athletics, 2016 London Anniversary Games, Queen Elizabeth Olympic Park, Stratford, London on July 23, 2016. Canada's Brent Lakatos crashes with athletes during the mens 1500m T54. (Photo by Eddie Keogh/Reuters/Livepic)

Chocolate is the greatest gift the Earth has given us. The dessert table would be a sad sight without it. It’s so beloved, so appreciated, that the Swedish scientist who named the cocoa plant that gives us chocolate called it Theobroma cacao, which means “food of the gods”. Here: Farmer holding a freshly cut cocoa bean pod, revealing the pulp and seed inside on a rainforest farm. (Photo by Doug McKinlay/Getty Images)

Muslim pilgrims pray around the holy Kaaba at the Grand Mosque, during the annual haj pilgrimage in Mecca September 30, 2014. (Photo by Muhammad Hamed/Reuters)

Runners cross the Verrazano-Narrows Bridge shortly after the start of the New York City Marathon in New York, November 2, 2014. (Photo by Lucas Jackson/Reuters)

A Mai-Mai rebel soldier shows off his guns at a checkpoint near the Mugunga refugee camp in Zaire; 1996. (Photo by Carol Guzy/The Washington Post)