Good thread! Although I agree with Chaltab that thinking too much about the implications of time travel is enough to drive a guy nuts. Anyway, I brought up 12 Monkeys, and if I'm wrong about anything, please feel free to correct me. But the way I saw it, there is only one timeline, with no possible offshoots/branches, unlike BTTF, Terminator, Bill and Ted, Timecop, ect. Bruce Willis isn't sent back to change the past, implying that it isn't possible. He was sent back to the past to determine where the virus originated and other relevant details, so that they can effectively fight it in the present (that being 2019 or whatever). I just thought it was clever and unique.