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)

Bangladeshi fisherman feed their otters as they catch fish in Narail some 208 kms from Dhaka on March 11, 2014. The fishermen are using a rare technique that relies on coordination between man and trained otters, a centuries-old fishing partnership that has already long died out in other parts of Asia. (Photo by Munir Uz Zaman/AFP Photo)

(L-R) Ozzy Osbourne and son, producer Jack Osbourne visit the Tribeca Film Festival 2011 portrait studio on April 25, 2011 in New York City. (Photo by Larry Busacca/Getty Images for Tribeca Film Festival)

Dance Team Rage Crew perform at BAFTA LA's 6th Annual Christmas Party and Toy Drive at Helen Keller Park on December 17, 2011 in Los Angeles, California. (Photo by Frazer Harrison/Getty Images)

A painting of a Trabant car bursting through a wall in post unification Berlin, August 1993. (Photo by Steve Eason/Hulton Archive/Getty Images)

Dutch collaborators under arrest at Nijmegan, Holland. They were rounded up after the capture of Nijmegan Bridge by the Allies. (Photo by H. Warhurst/PNA Rota/Getty Images). 1945

A Bangladeshi girl watches from a nearby building after a five-story building was raided by police in Dhaka, Bangladesh, Tuesday, July 26, 2016. Police in Bangladesh's capital raided a five-story building Tuesday that was used as a den by suspected Islamic militants, killing nine of them, the country's police chief said. Police said they belonged to a Bangladeshi group blamed for an attack on a Dhaka cafe earlier this month in which 20 hostages, mostly foreigners, were killed and had been planning another large-scale assault. (Photo by AP Photo)

A heat-stressed koala waits as a resident pours water on its back on December 19, 2015 in Adelaide, Australia. Adelaide is experiencing an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days. (Photo by Morne de Klerk/Getty Images)