A lot of films made in the early 1900s are no longer under copyright, because the copyright expired. This puts the films in the "public domain". You can have public showings and remix them for your own artwork without even needing to attribute the content to the original creator (you usually can't do this with films under copyright!).
Here's an example list of some films in the public domain in America:Porter Campus
1801 Massachusetts Avenue
Cambridge, MA 02140
617-349-8070
South Campus
89 Brattle Street
Cambridge, MA 02138
617-349-8850