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 topless woman walks through Bryant Park following the protest march called the GoTopless Day Parade Sunday, August 23, 2015, in New York. The parade took to the streets to counter critics who are complaining about topless tip-seekers in Times Square. Appearing bare-breasted is legal in New York. But Mayor Bill de Blasio and police Commissioner Bill Bratton say the body-painted women in the square who take photos with tourists are a nuisance. (Photo by Kevin Hagen/AP Photo)

A spectator at the Maslenitsa car battle, reacts during a clash, in the village of Goroshki, some 35 kilometers from Minsk, Belarus, 12 March 2016. The battle which is held at the Historical and Cultural Complex, Stalin line, is a small local competition, with participants from Belarus and Russia. (Photo by Tatyana Zenkovich/EPA)

A girl collects drinking water at Dala river outside Yangon, Myanmar March 3, 2016. Some 650 million people, or one in 10 of the world's population, have no access to safe water, putting them at risk of infectious diseases and premature death. Dirty water and poor sanitation can cause severe diarrhoeal diseases in children, killing 900 under-five a day across the world, according to United Nations estimates. (Photo by Soe Zeya Tun/Reuters)

Chen Ruolin of China performs a jump during the mixed team event final at the Aquatics World Championships in Kazan, Russia July 29, 2015. (Photo by Stefan Wermuth/Reuters)

Ramoncito Campo kisses his wife Hernelie Ruazol Campo on a flooded street during a southwest monsoon that battered Manila August 8, 2012. The newly-wed couple pushed through with their scheduled wedding despite severe flooding that inundated wide areas of the capital and nearby nine provinces. (Photo by Reuters/Courtesy of Ramoncito Campo)

“DC3 Wreck”. A capture of a US military DC3 plane wreck at the southern black beach in Iceland. Photo location: Iceland. (Photo and caption by Naian Feng/National Geographic Photo Contest)

China's Shang Chunsong prepares to compete in the uneven bars event of the women's individual all-around final artistic gymnastics competition at the Namdong Gymnasium Club during the 17th Asian Games in Incheon, in this September 23, 2014 file photo. (Photo by Kim Hong-Ji/Reuters)