The Government Bunker (Regierungsbunker) in Germany, officially named Ausweichsitz der Verfassungsorgane des Bundes im Krisen- und Verteidigungsfall zur Wahrung von deren Funktionstüchtigkeit (AdVB), in English: "Emergency Seat of the Federal Constitutional Organs for the State of Crisis or State of Defence to Maintain their Ability to Function" was a massive underground complex designed to house the German government, parliament and all federal personnel needed to keep the government working in the event of war or severe crisis. Located only about 25 kilometres (16 mi) south of Bonn, Germany (the capital and government seat of pre-unification West Germany), in the Ahr Valley between the towns of Ahrweiler and Dernau, it was one of the best kept secrets of West Germany.