On Jan. 15, 1974, "Happy Days" debuted on ABC.
The sitcom depicting the lives of the Cunningham family and their friends during the 1950s ran for 11 seasons from 1974-1984.
Many fondly remember the beloved sitcom, but a few facts may have been forgotten over time. Take a look below at some trivia from one of America's all-time favorite TV series.
We all know Richie and Joanie, but the Cunninghams had a third child, older brother Chuck, who mysteriously disappeared during the first season. Watch a scene featuring him below:
If the pilot above looks different from the show you remember that's because the series was shot as a single-camera show for the first two seasons, before switching over to the multi-camera sitcom version we all remember.
In the series the Cunninghams officially lived at 565 North Clinton Drive, Milwaukee, Wis., but the actual exterior shots are of a house in Los Angeles located at 565 N. Cahuenga Blvd.
It was thought that George Lucas' "American Graffiti" influenced "Happy Days," when in fact the series began its life as a segment on "Love, American Style."
Everyone remembers Ron Howard as the star of the series, but he only stayed on for the first seven seasons. He eventually returned for some guest appearances in the final season, and wrapped up his storyline when he moved to Hollywood with his wife, Lori-Beth to become a screenwriter.
After Howard left the show, Henry Winkler (The Fonz) got top billing during the opening credits.
Where is the Fonz's jacket now? It was on display at the Smithsonian for years until it was switched out to make room for Farrah Fawcett's iconic swimsuit:
... but if you need your Fonz fix, there's always the statue of him in Milwaukee.
Speaking of the Fonz, his full name is Arthur Herbert Fonzarelli.
... and then there was that time the Fonz almost got in a fight with Tom Hanks.
There were popular spinoffs of "Happy Days" like "Laverne & Shirley," "Mork & Mindy" and "Joanie Loves Chachi," but there was also an animated spinoff called "The Fonz and the Happy Days Gang" which didn't prove as popular. Once the animated series was canceled The Fonz and his dog moved over to the animated spinoff of "Laverne & Shirley" entitled "Laverne & Shirley In The Army."
"Sit on it" became a popular catchphrase on "Happy Days." Check out the Nick at Nite jingle dedicated to it below, but be warned: the song will get stuck in your head.
"Jumping the Shark" is a popular phrase in television today, indicating that a show has gone past the point of no return and has changed from the series you fell in love with. The phrase originated from the Season 5 three-part premiere when Fonzie goes water skiing and literally jumps over a shark. TV fans say that "Happy Days" was never the same after the shark incident (though the series ran for another six seasons after the infamous scene). Judge for yourselves when you watch the ridiculous scene below.
Happy Anniversary, "Happy Days!"