the local population. During August and September 1942, the Sonnenstein killing center was closed and incriminating installations such as gas chamber installations and crematorium ovens dismantled. After October 1942, the buildings were used as a military hospital. This part of the town's history was largely unrecognized in Germany until 1989, but after the regime change which was happening during this period, efforts to remember these catastrophic events began. In June 2000 a permanent exhibition opened, and today a small plaque at the base of Sonnenstein Castle together with the Sonnenstein Memorial provide remembrance. At the end of the war several air raids took place mainly targeting the railway station in Pirna and the Děčín–Dresden Railway. The air raid on April 19, 1945, destroyed all railway tracks and also the bridge over the Elbe. Thought there were only strategic targets most of the over 200 dead were civilians. During the GDR and Socialism During the existence of the GDR and its economic model, a so-called planned economy, people mostly worked in publicly owned enterprises: the artificial silk factory (which formerly belonged to Hugo Küttner, a well-known artificial silk business owner) established at an industrial zone located near today's B 172 the cellulose fiber factory (its location has been between the railway line & the Gottleuba river flowing into the Elbe) the VEB Strömungsmaschinen Pirna (a builder of hydraulic machinery) on the Sonnenstein, originally being founded in 1956 as VEB Entwicklungsbau Pirna the Wismut in Königstein Among other things, Pirna 014 turbines for the 152 jet aircraft developed in the GDR were built at VEB Strömungsmaschinen. All these businesses did not continue to exist for long after reunification, because they were not competitive. The Elbe river was heavily polluted by industry wastewater, especially from the cellulose fiber factory; swimming in the river was no longer possible without dangers to health. In the mid-1980s, around 1,700 un-renovated apartments stood empty in Pirna, 400 of them in the old town. Individual particularly badly dilapidated houses were demolished in the period that followed, for example a house on the southeast corner of the market square and the so-called Kern’sche Haus in the Burgstraße. When in 1989 the Teufelserkerhaus was to be torn down as part of demolition measures in the old town, public demonstrations happened with people shouting “Save Pirna”. From this circle, the Kuratorium Altstadt (literally Old Town Board of Trustees) was formed, which