Also, the name given in
Nazi Germany to the program that caused the
murder of thousands of
handicapped,
retarded and
mentally ill germans in the
Dachau concentration camp near
Munich from 1935 to 1939.
The plan worked like this: They told the family that the person who was meant to be killed that he was going to a government owned spa, to better his chances of getting better. Over at Dachau, those people (many of them children) were gassed. Then a letter would be sent to the family informing them that their relative has suffered an unfortunate accident. In time as these letters became more and more common, people started to understand what was going on and pressured the government to stop it.
As was noted above, Opperation Euthanasia ended in 1939. However by that time the Nazi government has already performed several researches as to what gas would affectively be used in mass killing, a knowledge that was well used in years to come.