Assassin's Creed II/Sequence 14: Veni, Vidi, Vici

Before unlocking the final DNA Sequence in the game, you will need to collect all 30 Codex pages and arrange them in the Codex page room at your villa in Monterrigioni. Depending on what DLC if any you have, the memory of unlocking the location of the vault will happen at different times. If you've already beaten the game, then it won't matter since you've already played this sequence, but otherwise, at the farthest sequence you have – either Sequence 11, Sequence 12 or Sequence 13 – you will get a memory start icon at your villa to play the memory. If you don't have all the Codex pages, a memory will block your entrance.

During the Sequence 12 DLC, you obtain a map of the Codex page locations, and these will become visible on your map at this point, whether you've synchronized the viewpoint for that area or not. If you don't have the Sequence 12 DLC, you will just be told that Ezio acquired it during the missing memories, and it will just be given to you. When you have all the pages, bring them back to your villa and put them up on the wall. Using your eagle vision, rotate the pages until they line up in such a way that they show a map of the world. After this is accomplished, you will be able to access this last DNA Sequence.