In post-war times, only private memorial plaques in the arcade court served as reminders of the euthanasia and prisoner murders that took place at the castle. It was not until 1969 that the Upper Austrian State Welfare Society established a memorial in the rooms that had once served as a reception room and gas chamber at the euthanasia centre.
In 1997, the State of Upper Austria and the Upper Austrian State Welfare Society decided to combine the restoration of the castle with a new concept and contemporary design for the memorial. It was now possible for the first time to include all the rooms where the murders took place as historical places in the memorial.
The traces left by the euthanasia campaign on the building itself were isolated and secured. In addition, a cut made through the euthanasia rooms to reveal the organisation of the mechanised path of death represented a radical change to the structure of the building. A walkway leads through the cut and shows visitors the way. It is possible to walk through, but not enter euthanasia rooms, which provides the distance to the historical rooms that is considered necessary for dealing with the topic. The objective is to enable a critical approach to this place where people were murdered. It also possible to approach the subject from an emotional perspective, but this is not obligatory.
Right after the former euthanasia rooms follows a peaceful room for remembrance, meditation and prayer, which was designed by artist Herbert Friedl.
Outside of the building, the location of the former bus garage and the part of the garden where human remains from the crematorium were buried represent an integral part of the memorial. A mausoleum is located at the latter, where the remains of the victims of the Nazi euthanasia programme in Hartheim are interred.
Comprehensive historical information about the Nazi euthanasia programme and the role played by Hartheim Castle are offered in the former functional spaces of the castle.