Q: What do you say when you go back in time and see the S.S. Titanic pull up at the dock?
Wait, but if it only had one voyage, it... well, whatever, if you see it... WHATEVER, you know what I mean. It would be a joke that nobody but you and any other time travelers that happened to be there would get. Maybe not even the other time travelers because they might not have learned about the Titanic in their highly advanced culture. Or maybe they came from the past somehow and the Titanic hadn't been built in their time and they were planning on taking a nice trip on this incredible feat of technological whatever but the joke's on them, HAHA! Yeah.
A: Those lemmings sure did.