People ride a prototype of a driverless vehicle as it is moves through a pedestrian area in Greenwich, east London, February 11, 2015. Britain has begun testing driverless cars in four cities, launching the first official trials ahead of a series of planned rule reviews to accommodate the new technology. (Photo by Suzanne Plunkett/Reuters)

The Boeing 747-8 Intercontinental airliner, the company's newest and largest passenger plane, takes off for its first test flight at Paine Field Airport March 20, 2011 in Everett, Washington. The new plane features quieter, more fuel efficient engines, more seating and a redesigned interior.

Pope Francis waves as he arrives at the Kangemi slums on the outskirts of Kenya's capital Nairobi, November 27, 2015. (Photo by Goran Tomasevic/Reuters)

Three-month old cheetah cubs make their public debut at the Smithsonian National Zoo on July 24, 2012 in Washington, DC. (Photo by T.J. Kirkpatrick)

Elvish writing is seen on “Anduril”, a prop sword belonging to Aragorn, hero of “The Lord of the Rings” movie trilogy on July 31, 2014 in London, England. The sword, belonging to actor Sir Christopher Lee and estimated at $150,000-250,000, forms part of Bonhams “There's No Place Like Hollywood” movie memorabilia auction taking place in New York on November 24, 2014. (Photo by Peter Macdiarmid/Getty Images)

Cosplay enthusiasts Alex Lawson, 20, attends the North East Manga and Anime Convention (NemaCon) dressed as Hunni Sempai at Middlesborough Town Hall on June 18, 2011 in Middlesbrough, England. Hundreds of Manga, Anime and Cosplay enthusiasts gathered for NemaCon 2011. Cosplay is short for Costume Play where players dress and perform roles from Japanese culture, Anime and Manga art characters. Many subcultures have also evolved inspired by video games, American cartoons and comics. (Photo by Christopher Furlong/Getty Images)

Darts fan Nigel Panton in fancy dress ahead Day Eight of the William Hill PDC World Darts Championships at Alexandra Palace on December 28, 2014 in London, England. (Photo by Jordan Mansfield/Getty Images)