A man passes by an unfinished street art graffiti made in a stairway by French street artists Zag and Sia in Paris on March 1, 2016. The two artists drew inspiration from famous “Liberty Leading the People” (La Liberte guidant le peuple) painting by French Eugene Delacroix commemorating the July Revolution of 1830 and viewed as a symbol of the French Republic. (Photo by Joel Saget/AFP Photo)

Faithful carry a boat out to sea, filled with offerings to Yemanja, the African sea goddess, during a ceremony honoring the deity in Montevideo, Uruguay, Saturday, February 2, 2013. Thousands of worshippers come to the beach in Montevideo on her feast day, February 2, bearing candles, flowers, perfumes and fruit to show their gratitude for her blessings bestowed upon them. The belief in the goddess sprouts from Umbanda, a blend of religions that include African, Catholicism and Spiritism. (Photo by Matilde Campodonico/AP Photo)

This photo taken on December 2, 2015 shows a lenticular cloud forming as white streaks from airplanes mark the blue sky, in a rare atmospheric phenomena above the town of Gevgelija on December 2, 2015. Lenticular clouds have been regularly confused for UFOs throughout history due to the their smooth, round or oval lens-shaped structure. (Photo by Armend Nimani/AFP Photo)

Alex Plunkett, left, and Sean Hart, both of Arlington, Va., join hundreds participating in the annual International Pillow Fight Day on April 5. Massive pillow fights broke out on the Mall in Washington and in cities around the world. (Photo by Marvin Joseph/The Washington Post)

A Japanese girl participates in a calligraphy contest to the celebrate the New Year in Tokyo January 5, 2015. Over 3,000 calligraphers, having qualified in country wide competitions throughout Japan, took part in the annual contest to celebrate the new year. (Photo by Issei Kato/Reuters)

The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)

Auto worker Christopher Brower screws a component into the cab of a four-door F150 at Ford's Kansas City Assembly Plant where new aluminum intensive Ford F-Series pickups are built in Claycomo, Missouri May 5, 2015. (Photo by Dave Kaup/Reuters)

A young girls holds a ballot during the Greek referendum in Athens on July 5, 2015. Greek voters headed to the polls today to vote in a historic, tightly fought referendum on whether to accept worsening austerity in exchange for more bailout funds, in a gamble that could see it crash out of the euro. (Photo by Aris Messinis/AFP Photo)