National Treasure was never intended to be a franchise. When the first installment did well, the filmmakers started from scratch to come up with a sequel. This time, though, they built in a potential part three. National Treasure: Book of Secrets mentions the mysterious page 47 of the president's secret book, which could be whatever they decide it should be in National Treasure 3.

Star Nicolas Cage gave the screenwriters a lot to live up to with one simple improvisation. "The way we left the movie, the President asked Ben, 'What's on page 47?'" Cage said. "I wanted to figure out what I could say that would really make people interested in what's on page 47 without saying it, so I thought of the words 'life altering.' Whatever it is, it's going to have to be life-altering."

Director Jon Turteltaub is not holding himself to the page 47 idea. "We can always tell people that's the fourth movie," he said. "That doesn't work. I've actually seen movies that seem like they're setting up for the sequel and that wasn't the sequel."

Even producer Jerry Bruckheimer said that the mention of page 47 is as far as development on National Treasure 3 has gotten. "The writers might know, but I don't know," he said. "And they're not going to tell me now because they're on strike."

Still, Cage already has ideas. "I believe that it should become more and more International Treasure," he said. "I was very happy to see that we went to London, England and Paris, France, but I'd like to see the movie go wider still. I'd like to go into Africa, Egypt, Asia, and keep going. My hope is that Ben is recruited and he gets a dossier from these other countries about their history, and has to download it and learn it, and then try to go on these hunts on their behalf. That would be a lot of fun for me."