Pearl Harbour? Not the film's name, but it might trip someone up. Should have known Hachi. Tora! Tora! Tora!'s clue might also have been a bit more specific.
Agora was a really interesting albeit under-marketed film. The other two nobody has guessed are fairly obscure. One a Matt Stone and Trey Parker film made over Spring break while they were at the University of Colorado, Boulder (hilarious if amateurish), the other a disturbing and horrifying Chinese film that might have kicked off the whole torture porn genre- though not as disturbing as the true events the film was based on. If you didn't guess these movies you ought to check out all three.
Fun fact (spoiler alert): in the film version Agora, Hypatia is suffocated by her companion to avoid the fate of being stoned to death by the ignorant fanatical mob of early Christians; in real life she was flayed alive by that mob. But contemporary Christians complained that this movie made them look bad when the true story is actually much worse.