A bishop walks past a new street-art collage by Italian artist Maupal showing Pope Francis playing tic-tac-toe and drawing peace signs as a Swiss guard keep watches the street near the Vatican on October 19, 2016 in Rome. (Photo by Tiziana Fabi/AFP Photo)

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

Afghan security stands guard as a tractor eradicates a field of young poppy plants May 25, 2011, in Argu District, Badakshan, Afghanistan. (Photo by Paula Bronstein/Getty Images)

An instructor from the Tianjiao Special Guard/Security Consultant Ltd. Co, smashes a bottle over a female recruit's head during a training session for China's first female bodyguards in Beijing January 13, 2012. (Photo by David Gray/Reuters)

A soldier stands guard on the aircraft park of the Pyongyang Airport on April 3, 2011 in Pyongyang, North Korea. Pyongyang is the capital city of North Korea and the population is about 2,500,000.

Alejandro Simon of Spain prepares to serve during their Preliminary Phase Pool E match against Canada during the VISA FIVB Beach Volleyball International at Horse Guards Parade on August 10, 2011 in London, England. (Photo by Scott Heavey/Getty Images)

Trainers from Tianjiao Special Guard/Security Consultant Ltd. Co. engage trainees dressed in swimming suits as they crawl on the beach during a training session in Sanya, Hainan province January 8, 2012. (Photo by CHINA DAILY/Reuters)

An Afghan policeman stands guard as smoke and flames rise from the site of a huge blast struck near the entrance of Kabul's international airport, in Kabul on August 10, 2015. A huge blast struck near the entrance of Kabul's international airport on August 10 during the peak lunchtime period, officials said, warning that heavy casualties were expected. “The explosion occurred at the first check point of Kabul airport”, said deputy Kabul police chief Sayed Gul Agha Rouhani. (Photo by Shah Marai/AFP Photo)