The Battleship Potemkin

1925 Soviet film from Sergei Eisenstein, recognised as one of the most important and influential films in the history of the cinema.
The development and use of montage is indeed still innovative today. Eisenstein is at his best when he uses montage, in fact out of time, on scenes such as a hand going back to strike something ('out of time' in so far as it does not make strict chronological sense). When montage is used to create an atmosphere it is most stirring, though perhaps would have been more so were the music surrounding it different (maybe 'Strike' achieves this balance better, even if it does not display the same tightness in its mastery of the image, cut, and edit.
Of course we have the famous Odessa steps sequence, which remains perfectly timed, exciting, and capable of doing things with the form of film that excites even today.
As far as the rest of the film is concerned, Eisenstein does his best to tell a story that is near impossible to convey through the silent means. We have the result of not being quite without ambiguity, but Eisenstein through his cue cards just about keeps us up to date. The lack of characterisation (beyond tropes) is actually rather refreshing.
This is a hugely important film, and the use of montage is really the whole thing. This is great, and the film should be watched for that.