A prototype battery-powered plane, called Greased Lightning or GL-10 is pictured flying at NASA's Langley Research Center in this undated handout photo obtained by Reuters May 1, 2015. The plane, which has 10 engines and can take off like a helicopter and fly efficiently like an aircraft, is currently in the design and testing phase. (Photo by Reuters/NASA)

A man fires a weapon as he dances during a traditional excursion near the western Saudi city of Taif, August 8, 2015. Saudis usually party in such excursions as they celebrate weddings or graduations. (Photo by Mohamed Al Hwaity/Reuters)

Drummers perform during rehearsals at the Bird's Nest National Stadium ahead of the IAAF Athletics World Championships in Beijing on August 20, 2015. The Athletics World Championships will be held at the stadium from August 22 to 30. (Photo by Greg Baker/AFP Photo)

A giant Santa Claus, created and worn by local artist Ed Terrell, 66, walks home with his son and assistant, Rupanuga, 18, following a ceremony to decorate a scraggly Christmas tree with a single red Bulb in Reading, Pennsylvania, December 7, 2014. A ceremony to decorate the scraggly Christmas tree in Reading, Pennsylvania with a single red bulb, much like Charlie Brown's tree in the animated holiday classic, was postponed to Sunday from Saturday because of rain and cold temperatures, officials said. Officials decided to hold a re-dedication ceremony, which will include a Spanish and English reading from the movie's screenplay, and decorate it with a single red bulb, as in the 1965 animated television special, “A Charlie Brown Christmas”. (Photo by Mark Makela/Reuters)

This picture taken on January 25, 2015 shows a participant taking part in an ice water challenge in Zhangjiajie, central China's Hunan province. Participants were required to stay in an ice pond, holding an ice block while eating ice-cream with an electric fan blowing at them. (Photo by AFP Photo/Stringer)

A sloth peeks out from behind a door on a floating house in the “Lago do Janauari” near Manaus, Brazil, Tuesday, May 20, 2014. Manaus is one of the host cities for the 2014 World Cup in Brazil. (Photo by Felipe Dana/AP Photo)

Filipino typhoon survivor children, who escaped after their village was attacked by allegedly armed men, wait for social workers in the super typhoon devastated city of Tacloban, Leyte province, Philippines, 13 November 2013. Aid workers and relief supplies were being poured into eastern provinces hit by Typhoon Haiyan, which aid agencies and officials estimated has left thousands dead and staggering destruction in its wake. The official death toll in the Philippines from one of the world’s strongest typhoons rose to 1,833, the national disaster relief agency said with many towns still unaccounted for. (Photo by Dennis M. Sabangan/EPA)

Visitors crowd an artificial wave swimming pool at a tourist resort to escape the summer heat in Daying county of Suining, Sichuan province, China, July 11, 2015. (Photo by Reuters/Stringer)