Boston is a walker's town. It's as clear as the brick red path marking the Freedom Trail, the bright blue signs of the Harborwalk, and the green of the Emerald Necklace series of parks. Boston's nearly 400-year history has led to the development of hidden neighborhoods, historic sites, and iconic parks that tempt both Bostonians and visitors out onto the sidewalks, paths, and trails lacing this close-knit city. In addition, the Big Dig project, which helped revive downtown and the...