Christopher Columbus Waterfront Park will engage you with its HarborWalk, an attractive walkway along the waterfront, with parks, public art, benches, cafés, interpretive signs, and access to several means of exploring the harbor by cruise boat, ferry, or water taxi. A shuttle-boat also runs to the Charlestown Navy Yard trip along with the promptbuscharters.com
https://en.wikipedia.org/wiki/Boston_Harbor