Though it is Ghost Week on Tor.com all week, our not-so-subtle ulterior motive is to actually make it Ghostbuster week. In our view, it’s still one of the most perfect films of all time, and easily the best science fiction comedy. But sometimes what happened behind the scenes on a great film like this is almost as interesting as what we ended up seeing. Derived from the excellent director’s commentary track on the Ghostbusters DVDs, here are seven things you might not know about the boys in grey and the strange things going on in your neighborhood.

1.) New York Outside, LA Inside

The awesome New York City firehouse where the Ghosbusters set up shop is indeed a real, active firehouse located downtown in the Tribeca neighborhood of Manhattan. However, the interiors of the firehouse were all shot in another firehouse in Los Angeles. Adding to the believability of this, both firehouses were built in 1912, making them eerie duplicates of one another. According to Harold Ramis, the enthuasism from Dan Aykroyd over discovering the pole was genuine, so they just wrote the scene that way.

While the exteriors of the main branch of the New York Public Library are indeed the New York Public Library, and the interior scenes of the Rose Reading Room were really shot there (very early in the morning), all the initial scenes downstairs with the librarian being freaked out by the ghost were filmed in a library in LA. Finally, the interior of the Sedgwick hotel, where the Ghostbusters bag Slimer, is also in Los Angeles.

Ghostbusters is commonly thought of as New York movie, but often when the boys head inside, they are magically transported to Los Angeles.

2.) Ecto 1 Was One of a Kind

In the movie, Peter Venkman is very disappointed in how Ray wasted a ton of money on an antique hearse that needs a new set of everything. In fact, the actual car was one-of-a-kind, meaning the entire production crew was extremely nervous about anything happening to it. According to Ivan Reitman, the car actually broke down once on the Manhattan Bridge while filming the famous scene in which Ray and Winston are traversing the bridge and talking about the end of the world. By the time Ghostbusters 2 came out, very little had to be done to the car to make it seem like it was on its last legs in the introductory scenes.

3.) Sigourney Weaver Made Up Her Own Lines, Barked Like a Dog

Both Ivan Rietman and Harold Ramis say that Sigourney Weaver was desperate to do a comedy, and as such jumped at the chance to be in Ghostbusters. Apparently, because the script called for her transformation into a dog, Sigourney barked like a dog during her audition. She also considered herself to be something of the straight man in what was otherwise, in her head, a Marx Brothers movie.

She’s also largely responsible for how Dana speaks. The line in the original script when Dana tells off Venkman was originally “you don’t seem like a scientist. You’re more like a used car salesman.” Weaver changed this on set to “you’re more like a game show host.” And we can’t imagine Venkman any other way.

4.) Venkman’s Electric Shocks Were Based on a Real Experiment

Ramis and Reitman reveal that the scene in which Venkman ruthlessly gives electrical shocks is based in part on the infamous Milgram experiment, a social psychology experiment which measured how far individuals will obey authority, even if they are actively doing harm to others. Ramis says the purpose of this scene in Ghostbusters was to test the audience’s ability to accept their hero unfairly giving electric shocks to someone else.

5.) Filming Shut Down Traffic in New York and Offended Isaac Asimov

The famous finale of the film was (mostly) filmed on the real Upper West Side in Manhattan. Of all of the New York City shoots, this one caused the most chaos. Traffic was halted all the way down to Columbus Circle, Times Square, and then Union Square, as well as across Manhattan from Broadway to 9th Avenue. For those unfamiliar with the geography of NYC, this means half of midtown was shut down, including many major traffic arteries. (Maybe the Ghostbusters causing the blackout in the sequel is an homage to this?) In any case, while filming, New York resident Isaac Asimov visited the set with the express pupose of bitching out Dan Aykroyd. According to Harold Ramis, Asimov hated the whole thing because it prevented him from getting home and screwed up traffic to intolerable levels. Aykroyd is a huge Asimov fan, and in the words of Ramis “Danny was crushed.”

6.) Ghostbusters Relied on Many Low-Budget, Practical Effects

Discussions of awesome movies frequently incorporate the phrase “special effects” which is really a misnomer. “Special effects” in the olden days referred to what is now called “practical effects,” which really happened on the set. Wires to make things fly, actual pyrotechnics, etc. Early in the commentary, Reitman asserts that most people might assume things like the floating books at the beginning of the film were done “optically” when in fact they were simply books suspended on wires. Further, when the card catalogue drawers start popping out on their own and swirling around the poor librarian, Ramis lets us know that there were just some technicians behind a wall blowing air through copper tubing in order to make the cards swirl around so creepily. Harold Ramis says “picking up the cards after every take” got a little old.

7.) “Cross the Streams” Was Made Up While They Were Filming

Even a casual film aficionado will notice the famous climax of Ghostbusters is a little bit bullshit. Why is crossing the streams the solution to everything? Because Egon said it was destructive early in the movie, duh. (“Total photonic reversal!”) This kind of convenient plot device is evident in other 80s movies (“Don’t look at it, Marion!” Wait? How did he know that? What is it?) but as the Ghostbusters filmmakers reveal, this was literally made up while the movie was in production. They didn’t feel like they had a good way of defeating Gozer, so a concept was shoe-horned into the story to create a sense of continuity. (We all love this plan and are excited to be a part of it, but it is probably the one thing that sticks out as being a conveniently ad hoc in what is otherwise a perfect movie.)

Honorable mention: Slimer is the ghost of one of the first settlers of New York City.

A companion handbook to the Ghostbusters DVD set mentions that Slimer was born in the year 1500, which either makes him one of the Lenape tribe that were living in the region or makes him one of the crew of the original Spanish voyage that discovered the land New York City is built on today. (Settlement didn’t begin until a century later, which rules him out as Dutch.) Since Slimer seems like such a quintessentially New York City joker, we think he was one of the European discoverers, choosing in death to live in a land he became enchanted with in life, but never got to properly settle.

There are tons of more little tidbits on Ghostbusters out there, but these struck me as the ones no one talks about. One thing is for sure, no one ever made them like this!

Stubby the Rocket is the voice and mascot of Tor.com and is ready to believe you.