It's apparent that many of the exterior scenes for the series, excluding stock shots, were mainly shot on the same few exterior sets on the Paramount Pictures backlot, often with minimal to zero set dressing to disguise re-use, often in back to back episodes. One of the most obvious examples is in season two, with the distinctive T junction of "Brooklyn Street", especially as the large building façade, with its distinctive doorway, features extensively in the season two finale. Considering that Paramount and CBS were corporate siblings, via the CBS and Viacom connections, for most of the series run, its not unusual that exteriors were shot at the Paramount backlot, with interiors at the CBS Studio Centre.
Det. Stella Bonasera:
Mmm... something smells good.
Throughout the series, probably to avoid copyright infringement issues, incorrect references are made to the New York Subway system. On subway entrances, the 1, 2, and 3 lines are shown in yellow, when they are actually red. A character blames his lateness on the fact that the Q train was changed to an express, whereas in real life the Q is normally an express.
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