Image:Espionage.png Espionage is one of the core concepts in Civilization IV: Beyond the Sword. The following buildings produce or accelerate the production of the espionage resource: * Castle * Citadel * Intelligence Agency * Jail * Mausoleum * Sacrificial Altar * Scotland Yard * Security Bureau * Courthouse * Rathaus * Ziggurat * Palace In addition, the Spy specialist and Great Spy (when used as a specialist) also produce espionage.