Which is the controversial movie you have ever seen? brief it plz

I watched Caligula (1979)

the detail is given here from filmsite.com

This lavish Roman-Empire epic was written by Gore Vidal and co-financed by adult-oriented Penthouse magazine's producer Bob Guccione, though the script underwent several re-writes after the director and cast found Gore Vidal's interpretation unsatisfactory (Vidal later disowned it). It advertised itself as "the most controversial film of the 20th century" - and was the most expensive pornographic film ever made.

This was Hollywood's first big-budget ($15 million that later ballooned to $22 million), bizarre blockbuster sexploitation epic of 'classy' hardcore sex and gory violence - and it became both a critical and commercial disaster after a very limited theatrical release (due to fear of prosecution for obscenity). The objectionable film was originally intended to be high-art, with major stars (Malcolm McDowell as the infamous Roman emperor, John Gielgud, Helen Mirren, Peter O'Toole), but was described as a "moral holocaust" by Variety and reviewers considered it worthless fantasy trash.

The fim was notorious for its graphic and steamy sex scenes (including a large-scale orgy, masturbation, explicit sex acts, sexual depravity and decadence including a lesbian one between two Penthouse Pets Lori Wagner and Marjorie Thoreson (as Anneka Di Lorenzo) that was filmed later and inserted for prurient interest). Originally self-rated as X and shown as unrated in a 156-minute version, it was then severely edited for an R-rating down to about 105 minutes.