Castle Pinckney was once a great fortress, playing an important role in the national security of the United States. However, today it has fallen to decaying ruins on a tidal salt marsh submerged by water in the harbor of Charleston. As part of the school and national design competition, I analyzed the situation to create an architectural design response that would restore the castle and marsh to a useable and purposeful part of the community. The design engages visitors though education and experience, while incorporating the components of castle, cabin, and pavilion, and taking advantage of the unique environmental context.