It's Always Sunny in Philadelphia is often considered to be one of the funniest shows to air on television. Based on a group of narcissistic friends who own a bar together in Philadelphia, this show has been able to stay relevant since it first debuted 15 years ago. The cast is full of awesome actors who play their characters so well, that it is really hard to believe that they don't act like that off-screen.

Despite being incredibly popular among Philadelphians, the show is beloved by people from all over the country and even from around the world. 14 seasons later and fans are still religiously tuning in to see what antics "the gang" will get into next. There are a lot of interesting behind-the-scenes facts about the show that give insight on how this masterpiece of a sitcom came to be today.

Here are 15 behind-the-scenes facts about It's Always Sunny in Philadelphia.

15 The Pilot Cost About $100 To Make

It's Always Sunny in Philadelphia had humble beginnings when first starting out, as they managed to get a deal from FX after showing them the pilot, which only cost about $100 to make. This is certainly a different budget from the millions the show can spend on each episode for the newer seasons.

14 The Show Originated From A Bad Dream Rob McElhenney Had About A Man With Cancer And His Insensitive Friends

A bad dream had by creator Rob McElhenney basically started It's Always Sunny in Philadelphia. Rob once had a dream about what it would be like getting no sympathy from his friends if they found out he had cancer. That is what the plot of the pilot ended up being, which greatly showed how incentive "the gang" would be for seasons to come.

13 The Actors Never Actually Drink Alcohol While Filming

Drinking alcohol is something the characters of It's Always Sunny in Philadelphia are doing basically every episode. Rob McElhenney has stated that nobody is actually drinking on the set, because it would put the show at risk. These actors sure do a great job of making the effects of beer consumption feel very genuine however.

12 Danny DeVito Almost Drowned While Shooting An Underwater Scene

The finale of season 11 almost turned fatal for actor Danny DeVito while shooting an underwater scene. Danny had to be weighed down to stay underwater due to his buoyancy, but had seriously struggled to get back up to the surface, saying "he saw his life flash before his eyes" before being rescued.

11 Rob McElhenney Continued His Job As A Waiter During The First Season Of The Show

Rob McElhenney plays "Mac" on the show, and now has enough money to do what he pleases when not filming. This was not always the case for him though, as he used to work as a waiter in Hollywood before the show started generating enough money for him to focus completely on acting.

10 A Fan-Made 'It's Always Sunny In Moscow' Released An Entire Season In 2014

This sitcom is beloved by people all around the world, and there is even a fan-made Russian version of the show called It's Always Sunny in Moscow. This retelling of the show lasted for one season in 2014, and goes to show how influential the program has become.

9 Danny DeVito's Casting For The Second Season Saved The Show From Being Cancelled

The first season of It's Always Sunny in Philadelphia was not getting the viewership that FX was hoping for. FX wanted to add a big name actor such as Danny DeVito to the fold, and when the rest of the cast said they didn't want to make changes, they threatened to cancel the show.

Related: 10 Characters Who Hurt Classic Sitcoms (And 15 Who Saved Them)

8 Dee's Character Was Originally Supposed To Be The Voice Of Reason For The Gang

Kaitlin Olson's character of Dee Reynolds on the show is always the butt of the joke and can be very volatile. This is certainly a 180 from what her original role was supposed to be, which was going to be a more serious character considered as the reasonable voice of the gang.

7 The Ending Credits Have Secret Messages Embedded In Them

After each episode of It's Always Sunny in Philadelphia, the voices of Glenn Howerton, Charlie Day, and Rob McElhenney can be heard but it seems to be gibberish. It turns out they are hidden messages that can only be deciphered if played backwards. The messages themselves always seem to mention the word "brown" which fans are split on what they are referring to.

6 Rob McElhenney's Body Transformation On The Show Involved An Immense Amount Of Off-Screen Eating And Training

A fit Rob McElhenney once packed on 60 pounds of weight for a "Fat Mac" storyline. He was quickly able to get ripped again, and the many who think Rob did all this just for the sake of comedy would be wrong. Rob has stated that he was payed a significant amount of money to do the transformations.

Related: 20 Actors Who Transformed Completely For A Role

5 Rob McElhenney and Kaitlin Olson Own A Real Bar In Philly Called Mac's Tavern

The bar used for the filming of the television show is actually in Los Angeles, but there is still a piece of the show in Philadelphia with Mac's Tavern. Rob and his wife Kaitlin are both owners of this very real bar that you can find on Market Street in Philadelphia.

4 The Iconic Green Man Was Inspired By A Real Person

Green Man from It's Always Sunny in Philadelphia has become a staple at Philadelphia sporting events as someone always seems to be dressed in the green suit. Rob McElhenney said he got the character from one of his childhood friends who dressed in a green suit at a football game.

Related: 10 Fictional Characters Based On Real People

3 They Shoot Scenes On The Same Lot As Seinfeld Did

For the 13th season of the show, the filming was moved to Studio City in California, which used to be the home to the legendary sitcom Seinfeld. The cast of It's Always Sunny in Philadelphia paid homage to the show when "the gang" confused their lives with what happened in Seinfeld.

2 The First Working Title Of The Show Was 'Jerks'

'Jerks' could describe the way the characters act on the show, but good thing this was just a working title and didn't become the name of the show. It's Always Sunny in Philadelphia has become such a staple in comedy television today, and the name they went with fits the show better than what 'Jerks' could have done.

1 The Opening Credits Were Shot On A Digital Camera By The Creators As They Rode Through Philadelphia One Night

While gathering film for the opening credits of the pilot, the creators of the show actually drove around taking videos of Philadelphia with a digital camera. These classic shots are still used in the show today, and another interesting point being the fact that all the shots are at night despite the "sunny" used in the show's title.

Next: Brooklyn Nine-Nine: 15 Surprising Facts From Behind The Scenes