Participants ride horses, hold spears and wear historic armoured suits of the Middle Ages as they compete during the Saint George international knight tournament in Moscow, Russia, May 3, 2015. (Photo by Maxim Zmeyev/Reuters)

U.S. Marines, left, and South Korean Marines, wearing blue headbands on their helmets, take positions after landing on the beach during the joint military combined amphibious exercise, called Ssangyong, part of the Key Resolve and Foal Eagle military exercises, in Pohang, South Korea, Saturday, March 12, 2016. North Korea said Saturday its military is ready to pre-emptively attack and “liberate” the South in its latest outburst against the annual joint military drills by the United States and South Korea. (Photo by Kim Jun-bum/Yonhap via AP Photo)

Chloe Goodman attending the Fantastic Beasts and Where to Find Them European Premiere at Leicester Square, London. (Photo by Ian West/PA Images via Getty Images)

Su Daocheng rides his home-made mechanical horse vehicle on a street in Shiyan, Hubei province January 18, 2015. Su spent 2 months making this 1.5 metre high and 2 metre long horse, which weighed 250 kilograms with 4 legs and 2 supportive wheels, local media reported. (Photo by Reuters/Stringer)

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)

A dressed up Oakland Raiders fan poses for photos as she arrives at Azteca stadium in Mexico City, Monday, November 21, 2016. The Oakland Raiders face the Houston Texans at a sold out Azteca stadium. (Photo by Dario Lopez-Mills/AP Photo)

Chinelos (traditional costumed dancers) perform in front of San Andres Ocotlan church as part of continuing festivities to welcome the new year in Calimaya, Mexico on January 4, 2016. (Photo by Arturo Hernandez/Demotix/Corbis)