No matter how long you stay in Boston, you will always find something new to do. The Freedom Trail alone links fifteen historically important sites across a two-and-a-half-mile walk through the city center. Beyond history, there are parks to explore, world-class museums to visit, and some of the best live music and sports venues in the country.
Boston is compact enough that most attractions are walkable or a short T ride apart. Start at the Common, wander through the Public Garden, and let the city unfold from there.