Continuity mistake: Lila comes through the bead curtain with the poison lilacs wrapped in green tissue paper. She drops the flowers, and in the next shot of them on the floor, the blooms don't even remotely resemble the ones she was just carrying - and the green paper has disappeared altogether. (00:10:55)
How to Hatch a Dinosaur (2) - S3-E9
Continuity mistake: When Barbara delivers the rare book on paleontology to Professor Dactyl, during this scene Dactyl holds the book with its spine either facing toward the right or the spine facing the opposite way, depending on the angle of the shot. (00:07:00)
The Foggiest Notion (2) - S3-E12
Continuity mistake: When Batman finds Ye Three Bells at the docks, in the exterior shots the entry door has a handleset on the exterior side of the door, but in the interior shots when the entry door is open, we can see there's a door knob on the exterior side of the entry door. (00:06:25)
Continuity mistake: At the very end of the episode, when Batman, Robin, and Batgirl find out Joker is released from prison, one shot shows Joker in his usual pink suit. But in the very next shot, his suit is gray.
The Funny Feline Felonies (1) - S3-E16
Continuity mistake: When Catwoman shoots the bullet into Commissioner Gordon's office, about a quarter-inch of the bullet remains exposed. However, when Batman goes to pull it from the wall, about four times as much of the bullet is now exposed.
Penguin's Clean Sweep - S3-E20
Continuity mistake: After Batman has captured the last fruit fly, he goes to put the vial away in his utility belt. In the close up shot, his hands move toward the left side of the belt. The shot changes to a long view and his hands are now instantly coming up from the right side of his belt.
The Joker's Flying Saucer - S3-E24
Continuity mistake: Batman and Robin both leap into the Batmobile and roar out of the Batcave. But the stock shot used after that shows Batman alone in the car. (00:03:10)
The Joker's Flying Saucer - S3-E24
Continuity mistake: Aboard Joker's flying saucer, Alfred and Batgirl are sitting three feet apart, then shoulder-to-shoulder, then apart again, depending on the shot. (00:20:50)
The Entrancing Dr. Cassandra - S3-E25
Continuity mistake: The Batmobile returns to the Batcave by remote control. It's facing left when we get a brief, three-second shot of Batgirl talking to Batman and Robin. In the very next shot, the Batmobile has instantly turned itself around and is facing right. Its turntable (which was actually pushed manually by stagehands under the platform) didn't work quite that fast. (00:18:05)
Answer: There wasn't one singular city used. It was shot in and around various locations in California, plus on a lot of sets and backlots. Ex. Some scenes were shot in LA, some in Pasadena, some in Santa Barbara, etc.
TedStixon