Germany has inaugurated a memorial to more than 200,000 people with physical and mental disabilities who were killed by the Nazis after their lives were deemed "worthless".
The memorial in Berlin is close to monuments to the Jewish Holocaust victims and to the Nazis' gay and Gypsy, or Roma, victims.
The 24m blue glass pane stands on the site of a villa where the mass murder of patients at hospitals and mental institutes was co-ordinated, starting in 1940.
The euthanasia programme's methods included the use of gas chambers.
Sigrid Falkenstein, whose aunt was killed in 1940, said it was "a technology of killing tested and carried out for the first time on defenceless, sick and disabled people, a test run for all the Nazis' following programmes of mass eradication".