The (West) German Government Bunker near Marienthal was officially known as Ausweichsitz der Verfassungsorgane des Bundes im Krisen- und Verteidigungsfall zur Wahrung von deren Funktionstüchtigkeit (AdVB) or Alternative Headquarters for the Federal Constitutional Bodies in the event of a crisis or state of defence to maintain their ability to function. In essence it was a huge underground complex built between 1960 and 1971 from where the German Government could continue to operate from in the event of any disastrous event.
Despite its full tongue-twisting name, it’s codename was the simple Rose Garden. The site is around 25km south of Bonne in the Ahr Valley and contained almost 1,000 bedrooms and the same number of offices and conference rooms. The complex was also well supplied with kitchens, bathrooms, hospitals and of course, power, air handling and water plant.
The core of its construction was based on abandoned railway tunnels dating back to 1910, built in anticipation of World War I. Abandoned after the war, these tunnels were initially used for mushroom growing but were re-purposed in World War II as an underground factory. This factory was used to construct V2 rockets and launch vehicles, with forced and conscripted labour. The site was codenamed Lager Rebstock (Camp Vine). As the end of the war approached, the factory was abandoned and the tunnels became air-raid shelters.
After decommissioning in 1997, a photographic record of the bunker was made but the majority of the complex was gutted and sealed. A small section of tunnel near the entrance has been converted into a Cold War Museum which opened in 2008. This Dokumentationsstätte Regierungsbunker Museum has a cinema and some original and recreated exhibits and is open three days a week.