People in Mexico wave at U.S. Border Patrol agents on horseback patrolling the U.S.-Mexico border fence near San Diego, California, U.S., November 10, 2016. (Photo by Mike Blake/Reuters)

Vigilantes armed with automatic rifles patrol the streets of Bujumbura, a city plagued by killings and violence as Burundi's crisis deepens. Here: an armed vigilante holds an AK-47 rifle in the center Bujumbura, Burundi, November 20, 2015. (Photo by Goran Tomasevic/Reuters)

A Ugandan soldier, part of the 9,000-strong African Union Mission in Somalia, (AMISOM) walks through the Banadir soccer stadium on August 15, 2011 in Mogadishu, Somalia. The stadium, Somalia's largest soccer facility, had been under control by Islamic extremist Shabab militants for the past two years until they withdrew from the capital more than a week ago. (Photo by John Moore/Getty Images)

A South Sudanese People Liberation Army (SPLA) soldier patrols the streets in Malakal on January 21, 2014. (Photo by Harrison Ngethi/AFP Photo)

Brazilian navy soldiers watch a woman as they patrol the area at the Copacabana Beach before carnival festivities in Rio de Janeiro, Brazil February 14, 2017. (Photo by Sergio Moraes/Reuters)

A four-legged robot dog called SPOT patrols a park as it undergoes testing to be deployed as a safe distancing ambassador, following the coronavirus disease (COVID-19) outbreak, in Singapore on May 8, 2020. (Photo by Edgar Su/Reuters)

Police women ride Segways as they patrol at Guangzhou South Railway Station on Jaunary 4, 2012 in Guangzhou, China. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)