Although the metropolitan area of BOSTON has long since expanded to fill the shoreline of Massachusetts Bay, and stretches for miles inland as well, the seventeenth-century port at its heart is still discernible. Forget the neat grids of modern urban America; the twisting streets clustered around Boston. Common are a reminder of how the nation started out, and the city is enjoyably human in scale. As the third busiest port in the British Empire (after London and Bristol), it stood on a narrow peninsula. What is now Washington Street provided the only access by land, and when the British set off to Lexington in 1775 they embarked in ships from the Common itself. During the nineteenth century, the Charles River marshlands were filled in to create the posh Back Bay residential area. Central Boston is now slightly set back from the water, separated by the hideous John Fitzgerald Expressway that carries I-93 across downtown.