FORT MATANZAS NATIONAL MONUMENT
Take a short (and free) ferry ride to this small Spanish fort from 1740. Little kids will love it because there's a boat ride involved, and a great 'Junior Ranger Program' keeps their interest on arrival. (Ask for a booklet at the info kiosk at the entrance). Even adults will be surprised how much history a little island can hold. Really worth the trip, especially on a sunny day, but don't forget to bring water.