A prototype Rollkers transportation device is displayed during a press event at the Mandalay Bay Convention Center for the 2015 International CES on January 4, 2015 in Las Vegas, Nevada. The product is not a skate; it balances for you and when you place it on the bottom of your shoe, it gives you the ability for faster transportation based on walking. The balance CES, the world's largest annual consumer technology trade show, runs from January 6-9 and is expected to feature 3,600 exhibitors showing off their latest products and services to about 150,000 attendees. (Photo by Ethan Miller/Getty Images)

A girl dances in front of the digital art installation “Light in Dark” created by teamLab, a collaborative of Japanese digital artists, during a special exhibition of “Shake! Art Exhibition! and Learn and Play! teamLab Future Park” at National Museum of Emerging Science and Innovation (or Miraikan) in Tokyo, Japan, 19 January 2015. The exhibition is held through 01 March 2015. (Photo by Kimimasa Mayama/EPA)

A Citroen Aircross concept car is pictured during the media day at the Frankfurt Motor Show (IAA) in Frankfurt, Germany, September 15, 2015. The car show runs through September 27. (Photo by Kai Pfaffenbach/Reuters)

An aerial view of the Grand Mosque is seen on the second day of Eid al-Adha, during the annual haj pilgrimage in the holy city of Mecca September 25, 2015. (Photo by Ahmad Masood/Reuters)

A model takes selfie with mobile phone as she presents a creation from the Dolce & Gabbana Spring/Summer 2016 collection during Milan Fashion Week in Italy, September 27, 2015. (Photo by Stefano Rellandini/Reuters)

Bavarian farmers load their cows on a boat before they drive over the picturesque Lake Koenigssee, Germany, October 3, 2015. Before the winter season approaches the farmers have to drive their cattle down from their Alpine meadows to a narrow valley that can only be reached by boat. (Photo by Michael Dalder/Reuters)