Bridge on the River Kwai

I'm not sure that I'd call it an epic. To me an epic is a story with a broad scope, either in time or in large scale of events that had an impact on history. Often they are personal stories set against big backdrops. If this is considered an epic, it's largely because it bears the thumbprint of a director who made some of the great epics of the golden era of epics, particularly the massive Lawrence of Arabia.

Bridge over the River Kwai is a great film, but to me it's an action adventure film. It's from an era when those sorts of films actually cared about things like characters that were real and who were impacted/transformed by the events of the story. Back then, there was more to an action film than the quality of the explosions. And, as in the case of this film, one really good explosion was enough.