In 1940 and 1941 the National Socialists murdered 13,720 people, most of them mentally ill or retarded persons, in the former Pirna-Sonnenstein sanatorium, an institution that had been renowned for its humanist tradition. These people were killed in a gas chamber as part of the National Socialist programme of medical murders code named 'Action T4'. Over a thousand prisoners from National Socialist concentration camps also died at this site in the summer of 1941.
It is only since 1989 that public awareness of these nearly forgotten mass murders has gradually increased. Since 1991 citizens of the town of Pirna and relatives of the murder victims have worked through the organisation 'Kuratorium Gedenkstätte Sonnenstein e.V.' (Trustees of the Sonnenstein Memorial) to establish a memorial. The memorial at the historical site was inaugurated in June 2000. Since that time the memorial area and a permanent exhibition illuminate the history of this site.