Female pilot Anna climbs out the cockpit of Japanese electronics company Suidobashi Heavy Industry's newly unveiled robot “Kuratas” at the Wonder Festival in Chiba, suburban Tokyo on July 29, 2012. The “Kuratas” robot, which will go on sale with a price tag of one million USD, measures four meters in height, weighs four tons and has four wheeled legs that can either be controlled remotely through the 3G network or by a human seated within the cockpit. (Photo by Yoshikazu Tsuno/AFP Photo)

Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

An Afghan street vendor carries bread on his head ahead of the upcoming holy fasting month of Ramadan in Kabul, Afghanistan, Sunday, June 5, 2016. Muslims across the world will be observing the holy fasting month of Ramadan, when they refrain from eating, drinking and smoking from dawn to dusk. (Photo by Rahmat Gul/AP Photo)

A hungry cow smiles for the camera in Salzburg, Austria. One of a series of funny animal mugshots taken by Chanel Cartell and Stevo Dirnberger during their travels around the globe. (Photo by Chanel Cartell/Stevo Dirnberger/Rex Features/Shutterstock)

Britain Horse Racing, Royal Ascot, Ascot Racecourse on June 14, 2016. Racegoers in Britain and EU referendum themed dresses. (Photo by Toby Melville/Reuters/Livepic)

A view of the scene of a train accident after two commuter trains collided head-on near the town of Andria, in the southern region of Puglia, killing several people, Tuesday, July 12, 2016. (Photo by Luca Turi/ANSA via AP Photo)

Pakistani passengers ride on crowded train returning from their hometown and villages after celebrating the Eid al-Fitr holiday to mark the end of the Muslim holy fasting month of Ramadan, to Lahore, Pakistan, Monday, July 11, 2016. (Photo by K.M.Chaudary/AP Photo)

Sara Moni, dressed as the World of Warcraft's Sinestra, poses for photographers on day three of the Comic-Con International held at the San Diego Convention Center Saturday July 23, 2016 in San Diego. (Photo by Denis Poroy/Invision/AP Photo)