Five hundred replicas of the Stormtrooper characters from "Star Wars" are placed on the steps at the Juyongguan section of the Great Wall of China during a promotional event for "Star Wars: The Force Awakens" film, on the outskirts of Beijing, China, October 20, 2015. (Photo by Jason Lee/Reuters)

A replica of the Wall-E character is remotely controlled with a mobile phone by Bolivian student Esteban Quispe, 17, in Patacamaya, south of La Paz, December 10, 2015. Quispe built the Wall-E robot using materials he obtained from a rubbish dump in the town located in the Andean highland region. He hopes to mechanize agriculture in Patacamaya by making use of robots that operate on solar energy, Quispe told Reuters. (Photo by David Mercado/Reuters)

West Berliners crowd in front of the Berlin Wall as they watch East German border guards demolish a section of the wall on November 11, 1989. (Photo by Gerard Malie/AFP Photo)

Britain Soccer Football, West Ham United vs Manchester United, Barclays Premier League, Old Trafford on May 10, 2016. Police play football with a young West Ham fan before the match. (Photo by Eddie Keogh/Reuters/Livepic)

Philippine Marines from the Naval Special Operations Group (NAVSOG) storm the beach to simulate an “extraction” of a kidnapped victim as they kick off a five-day amphibious military exercise at the Philippine Marines training center in Ternate, Cavite province, about 50 miles (80kms) south of Manila, Philippines Thursday, September 24, 2015. The naval exercise dubbed PAGSISIKAP 2015 is aimed at enhancing capability of their fleet and forces as well as to strengthen interoperability of the Marines. (Photo by Bullit Marquez/AP Photo)

Iraqi Kurdish female fighter Haseba Nauzad looks through a pair of binoculars during a deployment near the frontline of the fight against Islamic State militants in Nawaran near Mosul, Iraq, April 20, 2016. (Photo by Ahmed Jadallah/Reuters)

A soldier helps another with her ear protection at the Terningmoen Camp in Elverum, Norway on March 23, 2017. Soldiers demonstrate their skills and tactics during a contract drill as they train to become part of the world's first all-female special forces unit, the Jegertroppen or “hunter troops”. (Photo by Carolina Reid/NBC News)

A man sledges on Primrose Hill with his daughter and their dog on February 5, 2012 in London, England. The United Kingdom is experiencing heavy snowfall with many areas affected. (Photo by Peter Macdiarmid/Getty Images)