Solana Plains (R) escorts a distraught Elijah West, cousin of Troy Davis, out of the Towaliga County Line Baptist Church that is across from the Jackson State Prison for the planned execution of inmate Troy Davis on September 21, 2011 in Jackson, Georgia. (Photo by Jessica McGowan/Getty Images)

Two guards perform an execution in China, one holding the gun, the other holding a mask over the victim's face. (Photo by General Photographic Agency/Getty Images). Circa 1925

DJI Phantom 3 Severe Crash - Train Bridge

A girl carries a picture of Sheikh Nimr al-Nimr, who was executed along with others in Saudi Arabia, during a protest against the execution in front of the United Nation's building in Beirut, Lebanon January 3, 2016. Sign reads, “The martyr scholar Nimr al-Nimr”. (Photo by Hasan Shaaban/Reuters)

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)