A man walks next to a section of the wall separating Mexico and the United States, on the outskirts of Ciudad Juarez, Mexico, November 12, 2016. (Photo by Jose Luis Gonzalez/Reuters)

An inmate with a tattoo of Santa Muerte (The Saint of Death) reacts in the Topo Chico prison, during a media tour, in Monterrey, Mexico, February 17, 2016. The director of a prison in northeast Mexico where 49 people died in a riot this week was accused of murder and detained, along with two others, a state prosecutor said on Saturday. (Photo by Daniel Becerril/Reuters)

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)

Ten segments of the Berlin Wall, which constitute the longest stretch outside of Berlin, are seen on display in Los Angeles, California September 18, 2014. On November 9, Germany will celebrate the 25th anniversary of the fall of the Berlin Wall. To mark the event Reuters Photographers around the world captured images of segments of the wall, which are kept as monuments in many countries from Taiwan to South Africa and Costa Rica. (Photo by Mario Anzuoni/Reuters)

A two-horse team street cleaner, with sprayer, squeegee, and roller at rear. New York, between ca. 1910 and ca. 1915. (Photo by NYC Municipal Archives)

Men help remove messages and prayers written by thousands of people addressed to God from the cracks in the Western Wall in preparation for the up coming Jewish Passover holiday on March 28, 2012 in Jerusalem's old city, Israel. All the notes once collected will be buried in a special place at the Mount of Olives.according tro Jewish law. Passover begins in the evening of Friday, April 6 and commemorates the story of the Exodus where the ancient Israelites were freed from slavery in Egypt. (Photo by Uriel Sinai/Getty Images)