The commonly used word is "Dystopia". http://dictionary.reference.com/search?r=2&q=dystopia

Dystopia is the word used to describe the opposite of a utopia. Another suggestion is "Somewhere" as the word Utopia literally means "nowhere" - it was invented by Thomas More in the early 1500s and comes from the greek words "ou-" meaning "not" and "-topos" meaning "place.

As has been said, dystopia. However, a more familiar idea could be "Hell." I'd say anyone's idea of hell is about as far from ideal as possible.

1) "Utopia (from Greek: οὐ, "not", and τÏŒπος, "place" [hence, "no place" or "place that does not exist"], as well as εá½–, "good" or "well", and τÏŒπος ["good place"]—the double meaning was probably intended) is a fictional island near the coast of the Atlantic Ocean written about by Sir Thomas More as the fictional character Raphael Hythloday (translated from the Greek as "knowing in trifles") recounts his experiences in his travels to the deliciously fictional island with a perfect social, legal, and political system. The name has come to mean, in popular parlance, an ideal society. As such, it has been used to describe both intentional communities that attempted to create an ideal society, and fictional societies portrayed in literature. The term is sometimes used pejoratively, in reference to an unrealistic ideal that is impossible to realize, and has spawned other concepts, most prominently "dystopia"." "Related terms - Dystopia is a negative utopia: a totalitarian and repressive world. Examples: George Orwell's 1984, Aldous Huxley's Brave New World, Anthony Burgess's A Clockwork Orange, Alan Moore's V for Vendetta, The Reality Bug, Margaret Atwood's The Handmaid's Tale, Evgenii Zamiatin's We, Ayn Rand's Anthem, Lois Lowry's The Giver, Samuel Butler's "Erewhon" or Chuck Palahniuk's Rant . - Eutopia is a positive utopia, different in that it means "perfect" but not "fictional". - Outopia derived from the Greek 'ou' for "no" and '-topos' for "place," a fictional, this means unrealistic or directly translated "Nothing, Nowhere" This is the other half from Eutopia, and the two together combine to Utopia. - Heterotopia, the "other place", with its real and imagined possibilities (a mix of "utopian" escapism and turning virtual possibilities into reality) — example: cyberspace. Samuel R. Delany's novel Trouble on Triton is subtitled An Ambiguous Heterotopia to highlight that it is not strictly utopian (though not dystopian). The novel offers several conflicting perspectives on the concept of utopia. Some questions have arisn about the fact that writers and people in history have used "Utopia" to define a perfect place, as utopia is a perfect but unreal place. A proper definition of a perfect and real place is "Eutopia"." Source and further information: http://en.wikipedia.org/wiki/Utopia 2) If you stick to logic and to the "etymology" of the word, the opposite of "a good place that does not exist" would be "a place that exists or that is bad" (or both). There is no single word for this. An existing place is not an utopia, but it is not necessarily bad...