There is television before Homicide: Life on the Street and there is television after Homicide: Life on the Street.
That’s not hyperbole: the Baltimore-set police procedural, which ran on NBC for seven seasons and 122 episodes (plus the feature-length Homicide: The Movie), is not merely one of the greatest dramas ever to come across the airwaves, it led directly to the “Golden Age of Television” of the following decade.