Heterotopia is a concept created by Michel Foucault.

Utopia is not to accomplish, not to localize, and exists as a mere reversed analogy to a real place.

Heterotopia is a realized utopia, a place, where all the contradictions of society and ideas might be lived.

Foulcault mentions quite a lot of possible heterotopia, as first those of crisis and passage like boarding school, military service or honeymoon, then the “abnormal” heterotopias like prisons, psychiatric clinics or senior homes and graveyards, then those heterotopias which can be in connection to everybody like cinema, theatre, park, museum, libraries, playgrounds, holiday-colonies, Haman, whorehouses, hotel-rooms, ships etc.....

The most important heterotopia is of course the language. Only by words you're able to express the impossible