Civil War Battlefield

The Civil War battlefield is a project that was worked on by Frank Heffley in books two to three, although he is

Frank working on his battlefield.

seen working on it in the first movie. During the second book, Frank is strict with Rowley because he is afraid Rowley might accidently wreck it. In the third book, after Frank threw away Tingy (Manny's favorite blaknet),Manny mercilessly destroys the battlefield, and it's not even mentioned in the fourth book.