an action movie possibly heist movie from the 60’s or 70’s where a group of men broke into an underground facility possibly a missile silo the movie used a lot of split-screen views so you can watch multiple actions at once.
it was most likely an american movie but its possible it was European.
sadly I do not know who was in it.
it seemed that the split-screen stuff was a big deal back then and that may be why it stuck in my mind or maybe it was just new to me.
Maybe Twilight’s Last Gleaming from 1977?