Description: Several underground manufacturing sites were built in the Third Reich in 1944-45, to protect vital industries from the Allied bombing campaign. Most of these sites consisted of underground tunnels, built in existing mines or new excavations (for example, see the Nordhausen, Kahla, and Ebensee pages). But a unique type of bunker was started near Mühldorf am Inn, east of Munich, called Project "Weingut I" (Wine Estate). This site was to consist of a long massive structure built from reinforced poured concrete arches. The subsurface earth would have been excavated from under the structure to provide a large working area. Design and heavy construction work was performed by the engineering firm Polensky & Zöllner, with manual labor by concentration camp inmates and Russian POWs from Dachau and other sites, who were quartered in nearby camps. (Other bunkers of this type were built near Landsberg (Weingut II and Diana II), and planned in the Sudetenland and the Rheinland.)
The site was planned for the manufacture of Me 262 jet aircraft engines and parts, and construction began in May 1944, but the site was not completed. Only half of the concrete arches were poured, and the underlying excavation was not finished, when the war ended. Other structures in the area included air raid protection bunkers, cement factories, and administration buildings.
The bunker structures were built by piling mounds of gravel on the ground, in the appropriate shape, and pouring concrete onto these to a thickness of three meters. The concrete was poured in separate arch sections. The finished bunker was to have consisted of twelve arches, for a total length of almost 400 meters. The underlying gravel was then excavated out, including a planned depth of 18 meters below the original ground level. An additional two meters of concrete would have been added, then earth would have been placed on top of all and planted, for camouflage.
Construction stopped in late April 1945, when the prisoners were force-marched toward Munich (resulting in many deaths), and the U.S. Army overran the site on 2 May 1945. All but one of the seven existing arches were collapsed by explosives in 1947.