As of Dec. 2015, "Caligula" is not available to watch online. The film is only available on Blu-ray and DVD, though these can be ordered through services such as Amazon.com and Netflix.
There are numerous versions of "Caligula," and the legal disputes over the film have made home video releases difficult. The original screenplay for the film was written by Gore Vidal, who envisioned it as a serious, in-depth examination of Caligula's abuse of power. Production of the film was troubled from the start, and Tinto Brass, the film's original director, was dismissed during the editing process. Bob Guccione, the founder of Penthouse, was a producer on the film, and shot several hardcore sex scenes to add to the film.
The graphic sexual imagery in "Caligula" made the film immensely controversial, and the film was brought to court in cities such as Boston and Atlanta on obscenity charges. The film was eventually settled as not obscene, but numerous edits of the film were made in an effort to appeal to audiences that would otherwise be put off by the film's sexual content. Five edits of the film were made, ranging from 102 to 156 minutes in length. The film was released on DVD and Blu-ray as the "Imperial Edition," which features the original, unrated release, as well as a newly edited version without the sexual content.