National Treasure 3: Benjamin Gates to Search for The Fountain of Youth ... or Atlantis ... or...

What's on page 47 in the President's book of secrets in National Treasure 2? Jim Hill seemed to know the answer. He wrote that the next installment would not have Gates traveling the globe looking for the Fountain of Youth as suggested by the fan community. Why? Disney wants to save that plotline for Pirates of the Caribbean 4. Instead, Hill heard that the plot description being circulated would have Gates look for a clean energy source that sank along with Atlantis.