A Felix Airways plane is seen after it was destroyed by an airstrike at the international airport of Yemen's capital Sanaa, April 29, 2015. Jets from a Saudi-led alliance destroyed the runway of Yemen's Sanaa airport on Tuesday to prevent an Iranian plane from landing there, Saudi Arabia said, as fighting across the country killed at least 30 people. Airport officials said the strikes set a civilian aircraft operated by Yemeni Felix Airways ablaze. (Photo by Khaled Abdullah/Reuters)

Kurdish guard women from the civilian protection unit which supports the Democratic Forces of Syria, cheer near the Syrian town of al Houl in Hasaka province, after the Democratic Forces of Syria took control of the area, November 14, 2015. A U.S.-backed Syrian rebel alliance on Friday captured the town of al Houl in Hasaka province, which had been held by Islamic State militants, a spokesman for the Kurdish fighters, part of the grouping, said. It was the first significant advance against IS by the Democratic Forces of Syria, which was formed last month. (Photo by Rodi Said/Reuters)

Two biplanes of the Team Breitling cross during a training flight prior the AIR14 air show in Payerne, Switzerland, August 29, 2014. (Photo by Peter Schneider/EPA)

Friends of Li Guojun drive a homemade tank-shaped vehicle in Kangping county, China. Li, a farmer who is a fan of tanks, spent six months with help from his friends to construct the almost 20-foot vehicle which weighs 2.5 tons. (Photo by Sheng Li/Reuters)

Williams Formula One driver Felipe Massa of Brazil crashes with his car in the first corner after the start of the German F1 Grand Prix at the Hockenheim racing circuit, July 20, 2014. (Photo by Kai Pfaffenbach/Reuters)

Humanoid robot bartender “Carl” interacts with guests at the Robots Bar and Lounge in the eastern German town of Ilmenau, July 26, 2013. “Carl”, developed and built by mechatronics engineer Ben Schaefer who runs a company for humanoid robots, prepares spirits for the mixing of cocktails and is able to interact with customers in small conversations. (Photo by Fabrizio Bensch/Reuters)

“Zeybeks”. That's Dance, Sunward and Zeybeks. (Photo by Hasan Baglar/2014 Sony World Photography Awards)

Kevin and Merith Starren have their picture taken by Merith's brother Mark Ernst (R) and nephew Logan Ernst (L) in front of a 50-foot snowman named “Granddaddy” in Gilman, Minnesota, March 6, 2014. (Photo by Eric Miller/Reuters)