Facebook CEO Mark Zuckerberg (L) watches a demonstration of the new Facebook video chat during a news conference at Facebook headquarters July 6, 2011 in Palo Alto, California. Zuckerberg announced new features that are coming to Facebook including video chat and a group chat feature. (Photo by Justin Sullivan/Getty Images)

3D interactive artist Joe Hill poses with one of his works as part of the VisitBritain tourism campaign at Circular Quay on September 6, 2011 in Sydney, Australia. (Photo by Mark Metcalfe/Getty Images)

A man watches Israeli Air Force planes fly over the Mediterranean Sea from a beach at Tel Aviv during an aerial show as part of celebrations for Israel's Independence Day to mark the 66th anniversary of the creation of the state, May 6, 2014. (Photo by Nir Elias/Reuters)

Smithsonian National Zoo biologist Leigh Pitsko releases a male lion cub for its swim test in the zoo habitat moat, in Washington May 6, 2014. Four, unnamed ten-week old lion cubs were tested today for their ability to swim and remove themselves from their zoo habitat moat. (Photo by Gary Cameron/Reuters)

Promotional models use their smartphones during their break at the Global Mobile Internet Conference in Beijing May 6, 2014. Mobile Internet industry executives, developers and investors from more than 30 countries took part in the Global Mobile Internet Conference in Beijing, the organiser said. (Photo by Kim Kyung-Hoon/Reuters)

Servicemen of “Kiev 12” military defence battalion react as they take part in a welcoming ceremony in central Ukrainian capital Kiev December 6, 2014. Servicemen of the battalion returned to Kiev after taking part in fighting in eastern Ukraine. (Photo by Gleb Garanich/Reuters)