Frank Sinatra and Sophia Loren, with the help of multitudinous Spanish extras, drag the largest cannon in the known world from one spot in Spain to another to keep the weapon out of the hands of Napoleon's army and eventually do some real damage to that army and its leadership.
TrustMovies (back then a Los Angeles-based high-school student not much interested in world history) saw the film upon its initial release. He remembered it as big and long and heavy and occasionally actionful. It still is. Based on the C.S. Forester novel, The Gun -- a title that is short, smart and on the nose -- the movie was re-titled in typical Hollywood fashion to THE PRIDE AND THE PASSION and then handed to the thinking-man's hack director Stanley Kramer to make "meaningful." Or money-making. The former didn't happen, and despite the starry cast, I don't think the latter did, either.
Olive Films, the first thing you may notice is that all those thousands of extras are actual people, not CGI effects. My, god -- how did they do it! (Despite some gorgeous architecture and scenery, some of the backdrops we see are noticeably hand-painted.) The film's very weak screenplay (by Edna and Edward Anhalt is given over to either logistics about the movement of that cannon or to the almost completely uninteresting would-be triangle love story in which Ms Loren's character moves from rebel leader Sinatra over to British military man Grant.
Boy on a Dolphin, with her Oscar-wining performance in Two Women still three years away.)