Portuguese model and Victoria's Secret Angel Sara Sampaio arrives at the amfAR Gala Cannes 2018 at Hotel du Cap-Eden-Roc on May 17, 2018 in Cap d'Antibes, France. (Photo by Mike Marsland/Mike Marsland/WireImage)

A municipal worker sits on a bench, next to a statue, in Nizhny Novgorod, Russia, during the 2018 soccer World Cup, Thursday, June 28, 2018. Nizhny Novgorod was a “closed city” during the Soviet era. It was known as Gorky until 1990 and it was here that dissident scientist Andrei Sakharov was held under house arrest. Now the city hosts six World Cup matches and is teeming with tourists. That was unthinkable in the Soviet era and even rare now in a city that is seldom visited by outsiders. (Photo by Vadim Ghirda/AP Photo)

Japan' s Kaori Sakamoto competes in the women' s single skating short program of the figure skating event during the Pyeongchang 2018 Winter Olympic Games at the Gangneung Ice Arena in Gangneung on February 21, 2018. (Photo by John Sibley/Reuters)

“The Boeing X-45 unmanned combat air vehicle is a concept demonstrator for a next generation of completely autonomous military aircraft, developed by Boeing's Phantom Works. Manufactured by Boeing Integrated Defense Systems, the X-45 was a part of DARPA's J-UCAS project”. – Wikipedia

Photo: Two X-45A Unmanned Combat Air Vehicles (UCAV) are shown to members of the news media July 11, 2002 at Edwards Air Force Base, California. The X-45A, developed by The Defense Advanced Research Projects Agency and the Boeing Company, is the first unmanned system designed from inception for combat missions. (Photo by David McNew/Getty Images)

A participant attempts to control his craft during the Red Bull Flugtag Russia 2015 competition in Moscow, Russia, July 26, 2015. Enthusiasts competed in disciplines on the longest distance of the flight, on the creativity of self-made aircrafts and on the originality of the performance in an attempt to win the contest, according to organizers. (Photo by Sergei Karpukhin/Reuters)

A tank rolls out from a ship on a landing operation during military drills at the Black Sea coast, Crimea, Friday, September 9, 2016. Russia has deployed cruise missiles, multiple rocket launchers, tanks and its latest anti-aircraft system at massive military drills in Crimea. The drills which began across southern Russia and Crimea earlier this week and involve over 120,000 troops are some of the largest exercises Russia has held for years. (Photo by Pavel Golovkin/AP Photo)

Russia' s Tiffani Zagorski and Russia' s Jonathan Guerreiro compete in the ice dance free dance of the figure skating event during the Pyeongchang 2018 Winter Olympic Games at the Gangneung Ice Arena in Gangneung on February 20, 2018. (Photo by Lucy Nicholson/Reuters)

Zhao Deli waves as he pilots his self-made “flying scooter” in Dongguan, Guangdong Province, China, 12 August 2018 (issued 16 August 2018). Inspired by a cartoon he watched as a child, Zhao Deli sold off his apartment in pursuit of his dream of building a flying scooter. (Photo by Aleksandar Plavevski/EPA/EFE)