Balal, who killed Iranian youth Abdolah Hosseinzadeh in a street fight with a knife in 2007, is brought to the gallows during his execution ceremony in the northern city of Nowshahr on April 15, 2014. The mother of Abdolah Hosseinzadeh spared the life of the her son's convicted murderer, with an emotional slap in the face as he awaited execution prior to removing the noose around his neck. (Photo by Araash Khamooshi/AFP Photo/ISNA)

A boy walks with toy guns as people ride an APC during a military show at the Finnish Gulf coast in St.Petersburg, Russia, Saturday, September 5, 2015. (Photo by Dmitry Lovetsky/AP Photo)

Two stallions confront each other at a horse fighting contest in Rongshui, China. More than 30 horses from surrounding regions took part in the traditional activity of the Lantern festival. (Photo by China Foto Press)

A biker passes by a pair of mailboxes in the Capitol Hill neighborhood November 6, 2012 in Denver, Colorado. Colorado is considered by most experts to be one of the key battleground state in this year's presidential election. (Photo by Marc Piscotty/AFP Photo)

Senator Barack Obama (D-IL) (R) stands in front of Senator Hillary Clinton (D-NY) as they arrive for U.S. President George W. Bush's annual State of the Union speech to a joint session of Congress at the U.S. Capitol in Washington in this January 23, 2007 file photo. Hillary Clinton announced her second run for the presidency on April 12, 2015 starting her campaign as the Democrats' best hope of fending off a crowded field of lesser-known Republican rivals and retaining the White House. (Photo by Larry Downing/Reuters)

An Egyptian passenger sits on the locomotive of a train as it leaves Cairo train station in Egypt, Wednesday, October 14, 2015. (Photo by Amr Nabil/AP Photo)

Vehicles clog a highway during a hazy day in Beijing, China, Wednesday, February 26, 2014. Beijing remained cloaked in hazardous white pollution hiding much of its skyline Wednesday, despite the announced closures or production cuts at 147 of the city's industrial plants. (Photo by Ng Han Guan/AP Photo)

People work with cocoa beans in Enchi June 17, 2014. Picture taken June 17, 2014. Ghana emerged as a success story during the 2000s, when war, political instability and a disastrous liberalization brought Ivory Coast's cocoa sector to its knees. Ghana's output more than tripled from 340,000 tons in the 2001/02 season to a record 1,025,000 tons a decade later. Strict controls cemented its reputation as a producer of top quality beans, establishing a brand that fetches a premium. (Photo by Thierry Gouegnon/Reuters)