Pirates of the Carribean: the fountain of youth is Atlantis

Contains possible spoilers.

It's obvious. How else do you explain Greek architecture where supposedly no one has been before. This makes sense if the film takes place in the Carribean (implied by the relative location of Ponce de Leon's ship). Keep in mind, this is the area of the world that houses both the Bermuda Triangle and the Bimini Road, both of which are associated with Atlantis.

But a Spanish explorer's cups were critical to the ritual.

I think that the first person to venture into an area in their world is able to force it to take shape according to their will.

Well, since we are given no information about the cups other than they are needed for the ritual and Ponce de Leon had them, it leaves the exact origin of the cups in question. The cups themselves might be from Atlantis or more likely the cups aren't really needed for the ritual at all, just the words on the cups are needed. We don't see them trying to use other cups, so the actual necessity of them is in question.

I don't know, look at the cursed Aztec gold, the magic compass, Davey Jones having a modern ship despite being supposedly ancient.

I think Pirates is actually about the philosophy that the will of great men shapes the world.