Ben Gates: Before the Civil War, the states were all separate. People used to say "the United States are..." It wasn't until the war ended that people started saying "the United States is..." Under Lincoln, we became one nation.
At the end of National Treasure 1, Riley has a Ferrari 360 Spider. At the beginning of Book of Secrets, when his car is being towed away, it's a Ferrari F430 Spider. At the end of the movie, he is given back a 360 Spider.