How Belgium Became a Hub for Extremists Listen Download Embed Share Share this on Facebook (Opens in a new window) Share this on Twitter (Opens in a new window) Share this via Email A police officer patrols in front of the Antwerp cathedral on January 16, 2015. Belgian police arrested 13 people during a dozen raids the previous night, smashing a plot to kill police officers. ( DIRK WAEM/AFP / Getty ) Produced by Jillian Weinberger Produced by PRI and WNYC