Couples take part in the “Love and Challenge Marathon” in Hanoi, Vietnam, 16 August 2015. Fifty couples, who are going to get married, participated in the event which is held the fifth time. This year, the winners of the marathon received a honeymoon trip to Malaysia. (Photo by Luong Thai Linh/EPA)

Developed for the British American Ambulance Corps, this new motorcycle ambulance is capable of speeding wounded soldiers 90 miles an hour from the front lines to field hospitals. Its springs are synchronized with the patient's heartbeat to avoid increasing fever when traveling over various Terrain. Viewing it in New York August 27, 1941, are left to right: constable Herbert Scott of England, driver; William E. Detlor, whose firm developed the vehicle; M. W. Stand, inspector-general of Civilian Defense, and Maj. Edward Riekert, also. (Photo by AP Photo)

Children wave Vietnamese and American flags while waiting for arrival of U.S. President Barack Obama (not pictured) before a welcoming ceremony at the Presidential Palace in Hanoi, Vietnam May 23, 2016. (Photo by Reuters/Kham)

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)

Cloud inversion taken at Sunrise in Mam Tor, Derbyshire, UK on August 30, 2016. (Photo by David Zdanowicz/REX Shutterstock)

A woman takes a selfie with “RoboThespian” at Robots, a major new exhibition at Science Museum in London, England on February 7, 2017. Exhibition showcases 500-year history of robots, with over 100 robots and the largest collection of humanoid robots ever displayed. (Photo by Tolga Akmen/Anadolu Agency/Getty Images)

Brittany Ching dressed as a character from the sci-film “Avatar” at the annual Denver Comic Con at the Colorado Convention Center on June 16, 2016. (Photo by AndyCross/The Denver Post)

American film director Mike Todd and his actress wife Elizabeth Taylor get into a spat after missing their flight from London to Nice on June 22, 1957. (Photo by AP Photo)