The city of Berlin unveiled a new monument this week dedicated to the estimated 200,000 people murdered by the Nazis solely on the basis of their physical and mental disabilities.
The 24-meter (79-foot) blue glass panel sits on the site of the villa where the Nazi’s euthanasia program was first coordinated, according to ABC News.
The extermination campaign was known as the T4, after the Tiergartenstrasse 4 office from which it was directed, according to BBC News.
“The murder of tens of thousands of patients and residents of care homes was the first systematic mass crime of the National Socialist regime,” Uwe Neumaerker, director of the memorial foundation, told the Daily Telegraph. “It is considered a forerunner of the extermination of European Jews.”
The monument is the fourth major memorial opened in the area in the past decade relating to Nazi atrocities, along with sites dedicated to Jews, gay people and Roma slaughtered in the Holocaust.