David Sharp, an engineer with Lockheed Martin, displays the “Samurai Flyer”, an aviation design inspired by the maple seed, during the Association for Unmanned Vehicle Systems International Conference August 16, 2011 in Washington, DC. Lockheed Martin unveiled the new design and demonstrated vertical takeoff and landing, stable hover, and on-board video streaming of the aircraft during their demonstration. (Photo by Win McNamee/Getty Images)

A dancer performs as visitors take pictures at an auto show in Tianjin, China April 28, 2016. (Photo by Reuters/Stringer)

A Virgin Atlantic passenger plane flies in the sky with the moon seen in the background, in London, Britain January 19, 2016. (Photo by Toby Melville/Reuters)

A participant runs through foam during the Love Foam Run race in Hsinchu, Taiwan May 29, 2016. (Photo by Tyrone Siu/Reuters)

This May 11, 2016 photo shows the backside of a bus decorated with a provocative mural, in Acapulco, Mexico. (Photo by Enric Marti/AP Photo)

Ecuadorian luthier Ivan Ibujes plays a guitar after repairing it at his shop in Quito, June 17, 2016. (Photo by Guillermo Granja/Reuters)

Sniper rifles sit on display for sale at the “Ready Gunner” gun store in Provo, Utah, U.S., June 21, 2016. (Photo by George Frey/Reuters)