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

A combination photo shows the faces of various attendees of New York Comic Con in Manhattan, New York, October 8, 2015. The event draws thousands of costumed fans, panels of pop culture luminaries and features a sprawling floor of vendors in a space equivalent to more than three football fields at the Jacob Javits Convention Center on Manhattan's West side. (Photo by Andrew Kelly/Reuters)

Chinese women wear face-kinis as they walk in to the water to swim at the beach on August 20, 2014 in the Yellow Sea in Qingdao, China. The locally designed mask is worn by many local women to protect them from jellyfish stings, algae and the sun's ultraviolet rays. (Photo by Kevin Frayer/Getty Images)

“Willy Rizzo was an Italian photographer and designer. In late 1948, Willy began an illustrious twenty-year career with Paris Match that would have him photograph some of the greatest names of the golden age of photojournalism. Married later to actress Elsa Martinelli, Rizzo enjoyed unparalleled access to the stars; Brigitte Bardot, Sophia Loren, Marilyn Monroe, Vivien Leigh, Audrey Hepburn, Jane Fonda, Gene Kelly, Fred Astaire, Salvador Dalí and Pablo Picasso all found themselves in front of Rizzo’s lens”. – Wikipedia. Photo: Jane Fonda, Studio Willy Rizzo, Paris, 1966. (Photo by Willy Rizzo)

Demonstrators take part in a mass “face-sitting protest” outside the Houses of Parliament in central London on December 12, 2014, as they protest against changes to p*rnography regulations. An amendment to the 2003 Communities Act applies the same strict rules to p*rn bought online as those included in the guidelines set out by the British Board of Film Censors for DVDs. The new laws ban films that feature s*x acts, such as spanking, caning, strangulation, aggressive whipping, humiliation, and face-sitting. Ministers say the rules have been brought in to protect s*x workers. But campaigners say it is an attempt to censor and control the internet. Paid-for videos shot overseas and viewed online in the UK are not affected by the new rules, which were introduced on December 2, 2014. (Photo by Leon Neal/AFP Photo)

Festival goers plays in mud during the 15th Annual Boryeong Mud Festival at Daecheon beach in Boryeong, about 190 km (118 miles) southwest of Seoul, July 15, 2012. About 2 to 3 million domestic and international tourists visit the beach during the annual mud festival, according to the festival organisation. (Photo by Chung Sung-Jun)

FaceResearch.org, a site run by two psychologists at the University of Aberdeen in Scotland, features software that can average together faces from thousands of photos. These images purportedly show the average face of women from 40 different nationalities.