Plimoth Plantation is a living history museum, where you get to "walk back in time" into the 17th century. This is great for my more literal kids, who have a harder time imagining some of the descriptions in the history books and novels we read.
Nicholas was so excited to visit the meeting house, because the top level of this structure was a lookout. With canons! ("Do they work, Mom?" "Are they real or just made like an art-project?")