Cambridge is NOT a suburb of Boston!
I have to correct
Kostya on that important point. Its like saying that
Brooklyn, NY is a suburb of
New York City. It is a grave insult, and in Brooklyn will get
youse a
beat-down. In Cambridge they're much more restrained, but inside they're hurt just as deeply by
Kostya.
To me a suburb is a satellite to an 'urb', a community whose main purpose in life is to service (typically, housing and green space) the metropolis. The Cambridge-Boston relationship (or the New York-Brooklyn relationship) is that of separate cities that grew up on opposite sides of a river, and both have their own raison d'etre. See Minneapolis-St. Paul.