A dystopia is a community or society, usually fictional, that is in some important way undesirable or frightening. It is the opposite of a utopia. Such societies appear in many works of fiction, particularly in stories set in a speculative future. Dystopias are often characterized by dehumanization, totalitarian governments, environmental disaster, or other characteristics associated with a cataclysmic decline in society. Elements of dystopias may vary from environmental to political and social issues. Dystopian societies have culminated in a broad series of sub-genres of fiction and are often used to raise awareness of real-world issues regarding society, environment, politics, economics, religion, psychology, spirituality, or technology that, if left unaddressed, could potentially lead to a dystopia-like condition in the future. For this reason, dystopias have taken the form of a multitude of speculations, such as pollution, poverty, societal collapse, political repression, or totalitarianism.