Sonnenstein Euthanasia Centre, Memorial center at Pirna-Sonnenstein Castle near Dresden, Germany

The Sonnenstein Euthanasia Centre is a memorial within Pirna-Sonnenstein Castle near Dresden that commemorates victims of the Nazi euthanasia program. The space includes permanent exhibitions, reconstructed cellar rooms and archives holding documents that trace the course of the T4 operation.

The Sonnenstein killing centre operated in the former Sonnenstein Castle fortress, where a mental hospital had been established in 1811. In 1940 and 1941 the Nazis murdered at least 14,751 people there, mostly psychiatric patients and people with intellectual disabilities, but also concentration camp prisoners, under the secret Aktion T4 programme. The gas chamber and crematorium were installed in the cellar of House C 16; operations began on 28 June 1940 with ten patients from Waldheim. The Pirna-Sonnenstein Memorial now commemorates the victims.

The memorial occupies the attic of House C 16, the building whose cellar held the gas chamber; the permanent exhibition opened there on 9 June 2000, commissioned by the Saxon Memorials Foundation. Visitors see the reconstructed basement rooms, prepared as a memorial from 1995 after archival and archaeological work between 1992 and 1994.

The memorial sits on a slope above Pirna and can be reached on foot from the train station via an uphill path. Group tours can be booked in advance, and the exhibitions are open to individual visitors during opening hours.

The killing centre carried the internal T4 code letter D, which appeared as a business reference on all its official correspondence. The gas chamber in the cellar of House C 16 was fitted with shower heads on the ceiling to pass as a bathroom. The ashes of victims were dumped on the institute rubbish tip or shovelled down the Elbe bank behind the building at night.