The Heim ins Reich initiative (German: Home in the Kingdom or Home in the Realm) was a policy pursued by Adolf Hitler starting in 1939 and largely responsible for the outbreak of World War II. The initiative attempted to convince people of German descent living outside of Germany that they should strive to unify their countries with Germany -- to bring them "home" into a greater Germany. Concurrent with this was the beginning of attempts to ethnically cleanse non-Germans both from Germany and from the areas intended to be part of a "Greater Germany," as well as attempts to Germanize those who were considered ethnically or racially close enough to Germans to be "worth keeping", such as the population of Luxembourg (officially, Germany considered these populations to actually be German, only in need of being brought home into the flock, so to speak). These attempts were largely unpopular with the targets of the Germanization, and the citizens of Luxembourg voted in a referendum 98% against becoming citizens of Germany.

See also: final solution, Holocaust, Nazism