The Phantom of Hollywood was one of the last films shot on the Metro-Goldwyn-Mayer backlot, which was being demolished at the time of filming. It’s actually a major plot point, as it takes the place of the backlot of Worldwide Studios, the fictional studio within this movie.
A disfigured actor — just like the Phantom of the Opera — is killing anyone that tries to take down the studio. There are some great shots of famous films of the past — The Philadelphia Story, Grand Hotel, Mutiny on the Bounty, The Wizard of Oz — juxtaposed with the sets that have fallen into disrepair.
In 1974, no one — perhaps save the Phantom — knew the value of this history.
This one has a great cast, with Jack Cassidy (father of Shaun and David), Broderick Crawford, Peter Lawford, Jackie Coogan, John Ireland, Kent Taylor, Corinne Calvet and more appearing. It was written by George Schenck, who the normal world may know as one of the main writers and executive producers of NCIS, but we know as the writer, producer and director of Superbeast (and the writer of Turkey Shoot, too!). Director Gene Levitt is best known for creating Fantasy Island.
You can download this from the Internet Archive.