Considered one of the most important films in the history of silent pictures, as well as possibly Eisenstein's greatest work, Battleship Potemkin brought Eisenstein's theories of cinema art to the world in a powerful showcase; his emphasis on montage, his stress of intellectual contact, and his treatment of the mass instead of the individual as the protagonist. The film tells the story of the mutiny on the Russian ship Prince Potemkin during the 1905 uprising.
You can stream Bronenosets Potyomkin (Battleship Potemkin) (1925) free and legally on OldReel, via the Internet Archive.
Yes — it is in the public domain and can be watched and shared freely.