Hollywood is a magical place, but probably the most amazing thing about the entertainment industry is that any city can be faked.

Haven't you ever watched a show like 'It's Always Sunny in Philadelphia' and wondered where in Philly Paddy's Pub is? Well, don't go searching, because in real life, it's on the Fox lot in Los Angeles, California.

And just a few doors down from the 'Sunny' set is 'How I Met Your Mother,' where the gang gets in trouble on the streets of New York City ... that are actually on a sound stage in L.A.

But there are shows where there's no way the magic of the city can be faked ... right? 'Mad Men' is so completely New York in the 1960s (shoots in L.A., in the present day) and the rainy Seattle backdrop of 'The Killing' had to be 100% authentic (actually it was Vancouver's raindrops you saw all season).

We thought we'd take a look at a few of the other best tricked cities on TV ...

'Glee' (Fox)
Set In: Lima, Ohio
Films In: Los Angeles
Observation: 25th U.S. President William McKinely, the high school's namesake, is actually from the state of Ohio, but he was born in Niles, about 200 miles east of Lima.

'Grey's Anatomy' (ABC)
Set In: Seattle
Films In: Los Angeles
Fun Fact: 'Grey's Anatomy' has only shot a few key scenes and some exteriors in Seattle over the years -- and none of them was at Seattle Grace. One memorable adventure shot in Seattle was the guys camping trip back in Season 3 with Derek, Burke, George, Chief, Alex, bartender Joe and his boyfriend Walter.

'Fringe' (Fox)
Set In: Boston and New York
Films In: Vancouver
Fun Fact: The pilot was shot in Ontario and the rest of Season 1 was filmed in New York City before production moved to Vancouver, which means that Walter's lab has been built twice to match the pilot's original church basement filming location.

'How I Met Your Mother' (CBS)
Set In: New York
Films In: Los Angeles
Fun Fact: Most of the show's exterior scenes take place on what they call "New York Street" on the Fox lot. And if you don't think that's authentic enough, you should know that it's also where they shot award-winning drama 'NYPD Blue.'

'The Good Wife' (CBS)
Set In: Chicago
Films In: New York
Observation: Look closely at the trash cans in scenes set outside. A late Season 2 episode prominently features trash cans advertising keeping New York City -- not Chicago -- clean.

'Mad Men' (AMC)
Set In: New York
Films In: Los Angeles
Fun Fact: Instead of Sterling Cooper Draper Pryce overlooking Madison Ave., the show's set sits perched above the 110 Freeway in downtown L.A.

'CSI: Crime Scene Investigation,' 'CSI: Miami' & 'CSI: NY' (CBS)
Set In: Las Vegas, Miami & New York, respectively
Films In: Los Angeles & Long Beach
Observation: With Southern California cities acting as solid replacements for the desert, beach and Gotham City, it's surprising that the series hasn't just done an L.A.-based spinoff. (See 'NCIS' and 'NCIS: LA,' both of which shoot in L.A. as well.)

'The Killing' (AMC)
Set In: Seattle
Films In: Vancouver
Observation: The constant rain, from a sprinkle to a downpour, wasn't the only thing debated in this drama's first season -- fans were also annoyed at the characters' absolute lack of raincoats, hats or even umbrellas to shield them from the elements.

'Drop Dead Diva' (Lifetime)
Set In: Los Angeles
Films In: Peachtree City, Georgia
Fun Fact: Wondering how a show shooting in Georgia can get so many big-name guest stars to fly in for an episode? The small, quaint town of Peachtree City is less than 23 miles away from the Atlanta International Airport.

'House' (Fox)
Set In: New Jersey
Films In: Los Angeles
Observation: While 'House''s Princeton-Plainsboro Hospital is fictional, we can't imagine the cranky doc actually practicing medicine in sunny California. This is one cross-country city swap that really works.

'Weeds' (Showtime)
Set In: California, Mexico, New York City, Copenhagen
Films In: Los Angeles
Fun Fact: This show started in fictional suburban town Agrestic, California, moved to fictional beach town Ren Mar, then hit the road for Mexico, Seattle and Michigan before landing in New York and Copenhagen this season -- and it's all been shot in L.A.

'It's Always Sunny in Philadelphia' (FX)
Set In: Philadelphia, Pennsylvania
Films In: Los Angeles
Fun Fact: Every season, the cast and production go to Philly to shoot certain scenes on location for a week or more, so every location shot throughout the entire season is shot at once, all out of order.

'Psych' (USA)
Set In: Santa Barbara, California
Films In: Vancouver
Fun Fact: Santa Barbara gets around 17 inches of rain a year on average; Vancouver gets over two and a half times that, around 44 inches a year. And they call USA series "blue sky shows" ...

'Castle' (ABC)
Set In: New York
Films In: Los Angeles
Fun Fact: Itching to take the cop drama on the road, the cast was thrilled to hear there'd be a vacation episode last season ... until they found out their characters were headed to L.A., where they already shoot the show.


And What About These Fictional TV Cities?
Some shows choose fictional settings, but Bon Temps, Pawnee and Mystic Falls sure seem real, don't they? Here's where they really are.

'Community' (NBC)
Set In: Greendale, Colorado
Films In: Los Angeles

'The Vampire Diaries' (The CW)
Set In: Mystic Falls, Virginia
Films In: Atlanta, GA

'Parks and Recreation' (NBC)
Set In: Pawnee, Indiana
Films In: Los Angeles


'Cougar Town' (ABC)
Set In: Cougar Town, Florida
Films In: Los Angeles

'True Blood' (HBO)
Set In: Bon Temps, Louisiana
Films In: Los Angeles

'Desperate Housewives' (ABC)
Set In: Fairview, in "the Eagle State"
Films In: Los Angeles

'Eureka' (Syfy)
Set In: Eureka, Oregon
Films In: Vancouver


Follow Maggie on Twitter @TheTVShowGirl