The Charles River really is the lifeblood of the city of Boston and no trip to the city is complete without a run or a walk along the banks of this beautiful waterway, whichever part you explore. You can see boat houses, historic buidlings, homes, rowers, runners, cyclists, birds, mammals. Take a seat and people watch too. I ran a couple of times along different stretches of the river during recent stays. I felt incredibly revitalised after.