This is one of the more disturbing films I ever had the opportunity to watch. A college room mate of mine was a major film nut and had one of the most comprehensive collection of strange films I've ever seen. This was in his 'top 10'. It caused a lot of controversy back when it was released and continues to upset people today. The director, Pier Paolo Pasolini was murdered a few days after the film's release by being run over several times with his own car, dying on 2 November 1975 on the beach at Ostia, near Rome. Giuseppe Pelosi, a seventeen-year-old hustler, was arrested and confessed to murdering Pasolini. Thirty years later, on 7 May 2005, he retracted his confession, which he said was made under the threat of violence to his family. He claimed that three people "with a southern accent" had committed the murder, insulting Pasolini as a "dirty communist". Some conspiracy theories suggest the Catholic Church may have been involved in the murder plot.

For more info on the movie read the wiki content below:
Salò, or the 120 Days of Sodom (Italian: Salò o le 120 giornate di Sodoma), commonly referred to as Salò, is a controversial 1975 Italiandrama film written and directed by Italian director Pier Paolo Pasolini with uncredited writing contributions by Pupi Avati. It is based on the book The 120 Days of Sodom by the Marquis de Sade. Because of its scenes depicting intensely graphic violence, sadism, and sexualdepravity, the movie was extremely controversial upon its release, and remains banned in several countries to this day. It was Pasolini's last film; he was murdered shortly before Salò was released.

The film focuses on four wealthy, corrupted fascist libertines after the fall of Benito Mussolini's Italy in 1944 who kidnap a total of eighteen teenage boys and girls and subject them to four months of extreme violence, sadism, sexual and mental torture. The film is noted for exploring the themes of political corruption, abuse of power, sadism, perversion, sexuality, and fascism.

Although it remains a controversial film to this day, it has been praised by various film historians and critics, and while not typically considered a horror film, Salò was named the 65th scariest film ever made by the Chicago Film Critics Association in 2006 and is the subject of an article in The Penguin Encyclopedia of Horror and the Supernatural (1986).

The film is set in the Republic of Salò, the Fascist-occupied portion of Italy in 1944. The story is in four segments loosely parallel to Dante'sInferno: the Anteinferno, the Circle of Manias, the Circle of Shit, and the Circle of Blood.Four men of power, the Duke (Duc de Blangis), the Bishop, the Magistrate (Curval), and the President (apparently Durcet) agree to marry each other's daughters as the first step in a debauched ritual. With the aid of several collaborating young men, they kidnap eighteen young men and women (nine of each sex), and take them to a palace near Marzabotto. Accompanying them are four middle-aged prostitutes, also collaborators, whose function in the debauchery will be to recount erotically arousing stories for the men of power, who, in turn, will sadistically exploit their victims.

The story depicts some of the many days at the palace, during which the four men of power devise increasingly abhorrent tortures and humiliations for their own pleasure. In the Anteinferno segment, the captures of some victims by the collaborators are shown, and, later, the four lords examining them. The Circle of Manias presents some of the stories in the first part of Sade's book, told by Mrs. Vaccari (Hélène Surgère). In the Circle of Shit, the passions escalate in intensity from mainly non-penetrative sex to coprophagia. An infamous scene shows a young woman forced to eat the feces of the Duke; later, the other victims are presented a giant meal of human feces. The Circle of Blood starts with a black mass-like wedding between the guards and the men of power, after which the Bishop is sodomized by his assistant. The Bishop then leaves to examine the captives in their rooms, where they start systematically betraying each other: one girl is revealed to be hiding a photograph, two girls are shown to be having a secret sexual affair, and finally, a collaborator (Ezio Manni) and the black servant (Ines Pellegrini) are shot down after being found having sex. Toward the end, the remaining victims are murdered through methods like scalping, branding, tongue and eyes cut out as each libertine takes his turn to watch, as voyeur.

The film's final shot is of two young soldiers, who had witnessed and collaborated in all of the prior atrocities, dancing a simple waltz together.

Salò transposes the setting of the Marquis de Sade's book from 18th century France to the last days of Benito Mussolini's regime in the Republic of Salò. Salò, a nickname for the Italian Social Republic (RSI) because Mussolini ruled from this northern town rather than from Rome, was a puppet-state of Nazi Germany. The Nazis had used the opportunity to round up the many Jews living in that part of Italy and sent them off to extermination camps; heretofore, many Italian officials had refused to implement the "Final Solution". Additionally, during the RSI period, the Italian Fascist movement was able to build a completely totalitarian state. During the preceding twenty years of Fascist association with the Savoy monarchy of the Kingdom of Italy the Fascists had been restricted in some of their actions by the monarchy.