You can’t come to Boston without walking at least part of the 2.5 mile Freedom Trail. Any of the 16 historically significant sites the trail passes through will give you a taste of Boston history, and there are great pit stops along the way to recharge. On a nice day, start at the Old North Church, have lunch in the North End, then walk to the USS Constitution. You can take the water shuttle back to Central Wharf and enjoy outstanding views of Boston from the inner harbor.