This South Boston retreat juts into Boston Harbor and is the historic site of Fort Independence, a former sea defense, since 1634, although the existing structure dates to 1851. Today, Castle Island serves city dwellers who come to walk dogs or run the serene two-mile Pleasure Bay loop. Grab a hot dog and ice cream cone at the food stand, and then find a grassy patch facing Boston Harbor for views of passing ships and the Boston Harbor Islands. Open daily dawn to dusk.
Boston, MA 02127