From Wikipedia:
A cult of personality or personality cult arises when a country's leader uses mass media to create a heroic public image through unquestioning flattery and praise. Cults of personality are often found in dictatorships but can be found in some democracies.
A cult of personality is similar to general hero worship except that it is created specifically for political leaders.
The development of photography, sound recording, film and mass production, as well as public education and techniques used in commercial advertising, enabled political leaders to project a positive image like never before. It was with these circumstances in the 20th century that the best-known personality cults arose.
Generally, personality cults are most common in regimes with totalitarian systems of government, that seek to radically alter or transform society according to revolutionary new ideas. Often, a single leader becomes associated with this revolutionary transformation, and comes to be treated as a benevolent "guide" for the nation, without whom the transformation to a better future cannot occur. This has been generally the justification for personality cults that arose in totalitarian societies of the 20th century, such as those of Joseph Stalin and Adolf Hitler.
The criticism of personality cults often focuses on the regimes of Stalin, Hitler, Mao, Ceauşescu, Saddam Hussein, Kim Il-sung and his son Kim Jong-Il. During the peak of their regimes, these leaders were presented as god-like and infallible. Their portraits were hung in homes and public buildings, with artists and poets legally required to produce only works that glorified the leader. Other leaders with such cults include Eva Peron of Argentina and her husband Juan. The term cult of personality comes from Karl Marx's critique of the "cult of the individual" - expressed in a letter to German political worker, Wilhelm Bloss.
Nikita Khrushchev recalled Marx's criticism in his 1956 "Secret Speech" denouncing Stalin to the 20th Party Congress: "Comrades, the cult of the individual acquired such monstrous size chiefly because Stalin himself, using all conceivable methods, supported the glorification of his own person. . . . One of the most characteristic examples of Stalin's self-glorification and of his lack of even elementary modesty is the edition of his Short Biography, which was published in 1948. This book is an expression of the most dissolute flattery, an example of making a man into a godhead, of transforming him into an infallible sage, "the greatest leader," "sublime strategist of all times and nations." Finally no other words could be found with which to lift Stalin up to the heavens. We need not give here examples of the loathsome adulation filling this book. All we need to add is that they all were approved and edited by Stalin personally and some of them were added in his own handwriting to the draft text of the book."
Journalist Bradley Martin documented the personality cults of North Korea's father-son leadership, "Eternal (formerly Great) Leader" Kim Il-sung and "Great (formerly Dear) Leader" Kim Jong-il.
Kim Il-sung rejected the notion that he had created a cult around himself and accused those who suggested so of "factionalism." A US religious freedom investigation confirmed Martin's observation that North Korean schoolchildren learn to thank Kim Il-sung for all blessings as part of the cult.
Former President Saparmurat Niyazov of Turkmenistan is another oft-cited cultivator of a cult of personality.
During Niyazov's rule there was no freedom of the press nor was there freedom of speech. This further meant that opposition to Niyazov was strictly forbidden and "major opposition figures have been imprisoned, institutionalized, deported, or have fled the country, and their family members are routinely harassed by the authorities. Additionally, a silhouette of Niyazov was placed on the screen of all television broadcasts and statues and pictures of him were 'erected everywhere. For these, and other reasons, the US Government has gone on to claim that by the time he died, "Niyazovs personality cult...had reached the dimensions of a state-imposed religion.
University of Chicago professor Lisa Wedeen's book, "Ambiguities of Domination" documents the cult of personality which surrounded late Syrian President Hafez al-Assad. Numerous examples of his glorification are made throughout the book, such as displays of love and adoration for the "leader" put on at the opening ceremonies of the 1987 Mediterranean Games in Lattakia, Syria.