16 details you probably missed in 'Ghostbusters'

In exterior shots of the New York Public Library, a large set of scaffolding can be seen in front of the building.

This was part of an actual NYPL restoration and cleaning project that was going on in the early 1980s at the main branch.

When the Ghostbusters interview the librarian after she sees a ghost, Peter asks if anyone in her family had schizophrenia.

She says that her uncle thought he was St. Jerome.

St. Jerome is known as the patron saint of librarians and archivists in Catholicism.

A bookshelf falls toward the Ghostbusters when they're investigating the library, but none of the books on it move or fall.

They were likely secured to the shelf for the scene, but it makes it a little less realistic.

Before the Stay Puft Marshmallow Man stomps through Manhattan later in the film, the brand's logo and mascot can be seen two separate times.

There are Stay Puft marshmallows in Dana's kitchen when she unloads her groceries at the start of the film.

An advertisement for the brand can also be seen on the side of a building when the containment unit explodes.

When the Ghostbusters commercial plays in Dana's apartment, their phone number, 555-2368, is shown on the screen.

The fake number has been used in other movies and TV shows as well, including "Momento" and NBC's "The Rockford Files."

While chasing the hotel ghost, the Ghostbusters set a small fire after hitting the cleaning cart with their proton blasters.

When they discuss what to do next, a housekeeper can be seen in the background trying to use a spray bottle of what appears to be a cleaning solution to put out the fire.

But cleaning products are largely flammable.

When chasing the ghost in the hotel, the Ghostbusters just refer to it as a ghost or vapor.

The character's official name in the fandom is Slimer, but that didn't come until the 1989 sequel.

Ray generally refers to some of the ghosts in the movie as "slimers" though, so the term itself was used in this movie.

After trapping the Slimer ghost, Peter gives the hotel manager a price breakdown for their services.

While pricing the cost for the entrapment, Peter looks at Egon, who's holding up four fingers next to his face. Peter says that it'll cost $4,000.

When Peter moves on to the price for proton charging and storage, Egon discretely holds up one finger, prompting Peter to tell the manager it'll cost an extra $1,000.

When the Ghostbusters start becoming famous after trapping Slimer, they're featured in the New York Post.

But the photo in the article actually appears to be a shot from later in the movie when the trio shoots their proton blasters at the Stay Puft Marshmallow Man.

When Peter investigates Dana's apartment, the fallboard on her piano (the part that covers the keys) is closed when they walk into the room.

The keys are then visible when the two walk around the living room. But by the time they enter Dana's bedroom, it's closed again.

When the Ghostbusters make headlines in the Globe, one of the other stories visible on the cover is "Princess Di Expecting Again!"

Later, another Globe page hung up in Peter's office reads, "Triplets for the Princess."

The headlines help show how much time has passed since the team first caught Slimer at the hotel, but it's also a fun pop-culture reference.

Prince Harry was in fact born in 1984 when the movie was released, but he's not a triplet.

Dana is pulled through her front door on a chair when she's possessed by Zuul.

There's a rug in front of the chair at first. But once the chair goes through the door, there's a clear line behind it that appears to be the track it moved on.

There's a more pronounced line there than on the rest of the tiled floor, but it blends in fairly well if you're not looking for it.

During some of the moments that Zuul possesses Dana, his demonic voice can be heard.

The villain was actually voiced by the film's director, Ivan Reitman.

He also voiced Slimer in this movie and the sequel.

When the Ghostbusters confront Zuul, the building around them begins to crumble.

Although some of the bits of the building crash and shatter, one large boulder can be seen hitting a police barricade and bouncing right off of it.

Part of the Stay Puft Marshmallow Man's iconic look is a red tie attached to a blue sailor collar.

But his tie disappears the first time he's hit with the proton blast and doesn't reappear until later in the scene.

After the Ghostbusters destroy the Stay Puft Marshmallow Man, pieces of him cover the area of the city.

As the trio is being praised by the crowd, a group of priests can be seen in the background blessing one of the singed pieces of the mascot.