Germany is building a memorial to about 300,000 people murdered by the Nazis because of mental and physical disabilities or chronic illness.
Work on the memorial -- a 100-foot (30 meter) long light-blue glass wall -- began Monday. The memorial will be located in the center of Berlin near the current home of the Berlin Philharmonic, on the site of the Nazi office that coordinated the so-called euthanasia program.
Germany's state minister for culture, Bernd Neumann, said educating people about the crimes of the Nazis and honoring their victims remains an obligation for the country.
In recent years, several victims' groups, among them the Jews, Roma and Sinti, and homosexuals, have had memorials dedicated to them in Berlin.