Conjure up a list of cities considered world capitals of espionage. Those featured in movies and television, with their romantic atmosphere and scenery, include Vienna, Budapest, Berlin, London, Cairo, Tokyo, Shanghai, Hong Kong, Macau, Bangkok, and Saigon. 

Not to ignore the less romantic but important cities of Moscow, Beijing, and Washington, DC. 

By comparison, Brussels seems overlooked by spy novelists and film directors, but its unusual concentration of diplomatic missions to the European Union, NATO, and to Belgium itself brings a high ratio per square kilometer of diplomats and lobbyists—as well as spies. “Washington and Brussels compete for the largest number of embassies and other representations on earth” remarked an ICT (information and communications technology)  executive close to the Belgian authorities. He added that the spy agencies of numerous countries, including America, Russia, and China…