This past weekend in Pleasanton, California, a suburb of San Francisco, elite police teams from as far away as South Korea, Uruguay, and Jordan converged for the ninth annual Urban Shield Expo and Conference, one of the largest tactical-police summits in the world. According to the Alameda County Sheriff’s Office, which manages Urban Shield, almost 6,000 volunteers agreed to help SWAT teams coordinate with fire departments, healthcare providers, and other agencies to simulate responses to “mass casualty” events like attacks against law enforcement, mass shootings, and earthquakes. For 48 hours across five counties in Northern California, teams of police dressed like soldiers toted assault rifles down suburban streets and burst into buildings as part of a series of tactical exercises. By most accounts, Urban Shield is now one of the largest training events for militarized police in the world.