Swiss pilot Bertrand Piccard prepares for a test flight of the solar-powered Solar Impulse 2 experimental aircraft in Payerne November 13, 2014. The aircraft, weighing 2.4 tons with a wingspan of 72 meters, is fitted with more than 17,000 solar cells. An attempt to fly around the world in stages using only solar energy will be made in 2015. (Photo by Ruben Sprich/Reuters)

Dutch artist Daan Roosegaarde paid homage to Vincent Van Gogh's famous “Starry Night” painting by creating a glowing bike path relying on solar-powered LED lights. The 650-yard route which opened November 12, 2014 extends between Eindhoven and Neunen, Netherlands, where Van Gogh spent part of his life. Its the first event marking the 125th anniversary of Van Gogh's death July 29, 2015. (Photo by Pim Hendriksen/Studio Roosegaarde)

A bomb-laden Su-25 jet at the Hmeimim air base in December 2015. Russia's lease agreement obliged Assad’s military to safeguard the perimeter of the Hmeimim base, while giving Moscow legal jurisdiction over the facilities inside. Negotiating perimeter protection from Syria’s new rulers will be vital for the Russian bases in an era of wire-controlled drones immune to jamming. (Photo by AP Photo)

Wrestler Kairi Hojo jumps at her opponent Mieko satomura during their Stardom female professional wrestling show at Korakuen Hall in Tokyo, Japan, July 26, 2015. Professional women's wrestling in Japan means body slams, sweat, and garish costumes. But Japanese rules on hierarchy also come into play, with a culture of deference to veteran fighters. The brutal reality of the ring is masked by a strong fantasy element that feeds its popularity with fans, most of them men. (Photo by Thomas Peter/Reuters)

A migrant woman pulls a girl out of the water as refugees and migrants arrive on an overcrowded dinghy in rough sea on the Greek island of Lesbos, after crossing a part of the Aegean Sea from the Turkish coast, October 2, 2015. A record number of at least 430,000 refugees and migrants have taken rickety boats across the Mediterranean to Europe this year, 309,000 via Greece, according to International Organization for Migration figures. (Photo by Dimitris Michalakis/Reuters)

A Palestinian young woman from the Birzeit University looks on during clashes with Israeli security forces in Beit El, on the outskirts of the West Bank city of Ramallah, on October 7, 2015. New violence rocked Israel and the Israeli-occupied West Bank, including a stabbing in annexed east Jerusalem, even as Israel and Palestinian president Mahmud Abbas took steps to ease tensions. (Photo by Abbas Momani/AFP Photo)

A combination photo shows the faces of various attendees of New York Comic Con in Manhattan, New York, October 8, 2015. The event draws thousands of costumed fans, panels of pop culture luminaries and features a sprawling floor of vendors in a space equivalent to more than three football fields at the Jacob Javits Convention Center on Manhattan's West side. (Photo by Andrew Kelly/Reuters)

A passenger (C) climbs through the window of an overcrowded bus as limited public transportation operates in the city during the ongoing fuel crisis in Kathmandu, Nepal October 9, 2015. Nepal is considering air-lifting fuel, possibly from Bangladesh, as supply routes from India stay blocked by protesters opposing its new constitution, a short-term solution ahead of a key festival even as the government talks to China for help. (Photo by Navesh Chitrakar/Reuters)