A soldier poses with a Hythe Mk III Gun Camera during training activities at Ellington Field, Houston, Texas in April of 1918. The Mk III, built to match the size, handling, and weight of a Lewis Gun, was used to train aerial gunners, recording a photograph when the trigger was pulled, for later review, when an instructor could coach trainees on better aiming strategies. (Photo by Harry Kidd/WWI Army Signal Corps Photograph Collection via The Atlantic)

This artist's scoreboard displays a fictional game between Mars and Earth, with Mars in the lead. It refers to the success rate of sending missions to Mars, both as orbiters and landers. Of the previous 39 missions targeted for Mars from around the world, 15 have been successes and 24 failures. For baseball fans, that's a batting average of .385. The United States has had 13 successes out of 18 attempts, or a “batting average” of .722. NASA's Curiosity rover, set to land on the Red Planet the evening of Aug. 5, 2012 PDT (morning of Aug. 6 EDT), will mark the United States' 19th attempt to tackle the challenge of Mars, and the world's 40th attempt. (Image by NASA/JPL-Caltech)

American film star Marilyn Monroe (Norma Jean Mortenson or Norma Jean Baker). (Photo by Keystone Features/Getty Images). 1952

A eunuch dances during a rally to mark the congregation of thousands of eunuchs from different parts of India, in Jammu, India, Friday, March 13, 2015. The term eunuchs is used in India to describe transvestites, transsexuals and others who identify themselves as neither male nor female but as a member of a third gender. They traditionally survive by begging, dancing at weddings or blessing newborn babies and are frequently subjected to discrimination. (Photo by Channi Anand/AP Photo)

Participants climb over a wall at the “Tough Mudder” endurance event series in Arnsberg September 6, 2014. Competitors who took part in the endurance event saw themselves having to overcome various military style obstacles. (Photo by Ina Fassbender/Reuters)

A hot air balloon flies close to the ground in the Jezreel Valley in northern Israel during an international hot air balloon festival October 14, 2014. (Photo by Nir Elias/Reuters)

Italian police officers carry away a FEMEN activist during a protest in St. Peter's Square at the Vatican, Friday, November 14, 2014. Members of the Ukrainian feminist group Femen staged a protest against the upcoming visit of Pope Francis at the European Parliament and Council. (Photo by AP Photo)

A visitor holds an Israeli-made rifle during the 8th International Land and Naval Defense system exhibition, in New Delhi, India, on February 6, 2014. (Photo by Anindito Mukherjee/Reuters)