The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)

Russian servicemen stand next to a Russian Yars RS-24 intercontinental ballistic missile system before a rehearsal for the Victory Day parade, with the Moscow International Business Center also known as “Moskva-City” seen in the background, at a range in Moscow, Russia, May 5, 2016. (Photo by Maxim Shemetov/Reuters)

Robert Price of TREWGrip LLC demonstrates a TREWGrip handheld rear-type keyboard and air mouse for Apple and Android tablets at the “CES: Unveiled”, media preview for International CES, at the Mandalay Bay Convention Center in Las Vegas on January 5, 2014. (Photo by Robyn Beck/AFP Photo)

A man removes ice from an ice-covered car with a hammer in Postojna, Slovenia, on February 5, 2014. Cars stand entombed in a crystal-like casing near the deserted railway station in Postojna. Trees and electricity pylons lie felled in the snow by the sheer weight of ice enveloping them. (Photo by Srdjan Zivulovic/Reuters)

A young girls holds a ballot during the Greek referendum in Athens on July 5, 2015. Greek voters headed to the polls today to vote in a historic, tightly fought referendum on whether to accept worsening austerity in exchange for more bailout funds, in a gamble that could see it crash out of the euro. (Photo by Aris Messinis/AFP Photo)

In advance of Fleet Week performances, the U.S. Navy Blue Angels and Team Oracle aerobatics pilot Sean D. Tucker fly over the San Francisco Bay during a photo flight on Thursday, October 5, 2017. (Photo by Noah Berger/AP Photo)

Two wolfhounds take part in a dogfight in a stadium in the Kyrgyzstan capital Bishkek on November 5, 2017, during fights organized by a local breeders aiming to improve the Asian Shepherd breed, organizers said. (Photo by Vyacheslav Oseledko/AFP Photo)

A man dressed as a devil performs during a Krampus parade in Kaprun, Austria on December 5, 2017. Krampus is a mythical creature that, according to legend, accompanies Saint Nicholas during the festive season. Instead of giving gifts to good children, he punishes the bad ones. (Photo by APA-PictureDesk GmbH/Rex Features/Shutterstock)