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 young woman cools herself in a fountain in Budapest, Hungary July 6, 2015. Over the weekend, a heat wave has reached Hungary with temperatures topping 38 degrees Celsius (100.4 degrees Fahrenheit). (Photo by Laszlo Balogh/Reuters)

An officer wipes sweat off the face of a Chinese People's Liberation Army (PLA) honor guard soldier as they rehearse for a welcoming ceremony for New Zealand's Governor-General Sir Jerry Mateparae at the Great Hall of the People in Beijing, Tuesday, July 21, 2015. (Photo by Mark Schiefelbein/AP Photo)

This photograph released by Indian Space Research Organization shows its polar satellite launch vehicle lifting off from a launch pad at the Satish Dhawan Space Centre in Sriharikota, India, Wednesday, February 15, 2017. India's space agency said it successfully launched more than 100 foreign nano satellites into orbit Wednesday aboard a single rocket.(Photo by Indian Space Research Organization via AP Photo)

A man presents a self-made robot that local media reported is able to carry a person, in Heihe, Heilongjiang province, China, April 5, 2017. (Photo by Reuters/China Daily)

Jennifer Lopez Gets Loud for Hillary Clinton at Get Out The Vote concert on October 29, 2016 in Miami, Florida. (Photo by Larry Marano/Rex Features/Shutterstock)

A resident walks past big waves spilling over a wall onto a coastal road in the city of Legaspi in Albay province, south of Manila on December 14, 2015, as typhoon Melor approaches the city. More than 700,000 people fled the central Philippines amid threats of giant waves, floods and landslides as powerful Typhoon Melor approached the archipelago nation, officials said December 14. (Photo by Charism Sayat/AFP Photo)

Bob Steele, of Jefferson, Texas, positions his bears during The Great Bear Show at the Dubuque (Iowa) County Fair on July 25, 2012. (Photo by Jessica Reilly/Telegraph Herald)