Jared721 via Flickr//CC BY NA 2.0

There's more to the beloved Californian burger chain than Double-Doubles and their secret and not-so-secret menus. We'll bet even you regulars and superfans don't know some of these.

1. IN-N-OUT WAS CREATED BY A COUPLE OF NEWLYWEDS.

Our founders, Harry and Esther Snyder with their sons, Guy and Rich.

A photo posted by In-N-Out Burger (@innout) on

When it opened in October 1948, In-N-Out was California’s first drive-thru hamburger stand; its founders, Harry and Esther Snyder, were newly married. Harry was known to visit the local Baldwin Park markets every morning to pick up fresh ingredients, and Esther was in charge of the accounting.

2. IN-N-OUT REVOLUTIONIZED FAST FOOD.

In-N-Out is credited as the first chain to have a two-way speaker system for drive-thru ordering. The forward-thinking Harry installed the intercom system in 1948 so that you truly could get "in and out" of his tiny hamburger shack in a hurry. Until that point, drive-ins with carhops who took your order and delivered your food were the norm.

3. THAT YELLOW ARROW WASN'T ALWAYS THERE.

Our original "No Delay" sign.

A photo posted by In-N-Out Burger (@innout) on

The iconic large yellow arrow on the logo first appeared in 1954, replacing the original “No Delay” sign.

4. THEY DIDN'T SERVE FOUNTAIN SODA FOR THE FIRST DECADE. 

Mr.TinDC, Flickr // CC BY ND-2.0

In 1958, the company added fountain soda to the menu, replacing the bottles they had been selling for a decade. A 12-ounce drink was only 10 cents, and you could actually choose between Coke and Pepsi in the same location!

5. 'X' ACTUALLY MARKS THE SPOT.

Matt Northam via Flickr // CC BY NC ND 2.0

In 1972, Harry Snyder introduced the crossed palm trees that stand outside most In-N-Out locations. The idea came from the 1963 movie It’s a Mad, Mad, Mad, Mad World, where the characters hunt for a buried treasure hidden beneath four crossed palms.

6. THE COMPANY HAS A LONG ASSOCIATION WITH DRAG RACING.

From Harry Snyder's 50 percent investment in a new track in Irwindale in 1965 (where his burgers were sold in the concession stands) to Harry and Esther’s only grandchild (and heiress) Lynsi Snyder’s occasional trips out on the track, In-N-Out is a mainstay name around drag racing. According to the National Hot Rod Association, Lynsi has competed in the Super Gas and Top Sportsman Division 7 categories. "I like an adrenaline rush," Lynsi said last year. "My dad took me to the racetrack for the first time when I was 2 or 3. … Anything with a motor, that was in my blood." Lynsi, who has taken auto mechanic classes, often works on her own cars. 

7. IN-N-OUT EVEN HAD A CAR.

 J. Michael Raby via Flickr // CC-NC-ND 2.0

The company sponsored drag racer Melanie Troxel in 2010.

8. IN-N-OUT HAS ITS OWN "UNIVERSITY."

Don Barrett via Flickr // CC BY-NC-ND 2.0

Established in 1984, the university’s classes aimed to train service staff and managers on how to maintain quality across the board. According to Bloomberg Business, roughly 80 percent of the chain’s store managers rose through the ranks to become career team members.

9. "LOVE WALKS IN" AN IN-N-OUT.

Getty Images

Van Halen’s chart-topping 1986 album 5150 was fueled by In-N-Out burgers. "When I first joined the band, we must have eaten there at least three days a week," Sammy Hagar told Stacy Perman for her 2009 book In-N-Out Burger: A Behind-the-Counter Look at the Fast-Food Chain That Breaks All the Rules. "We were in the studio recording 5150, and we'd send someone to go get food, and we'd talk about sushi or pizza and always end up with In-N-Out."

10. MANY CELEBS LOVE IN-N-OUT.

Speaking of famous fans, high-brow chef Julia Child once told Larry King that In-N-Out was "awfully good," and she reportedly kept a list of store locations in her purse. And, famously, Paris Hilton explained away a DUI arrest in 2006 by telling Ryan Seacrest, "I was just really hungry and I wanted to have an In-N-Out burger!"

11. THEIR JINGLE IS SUPER CATCHY.

You can even get an In-N-Out Burger ringtone

12. THERE ARE HIDDEN BIBLE VERSES ON THEIR PACKAGING.

BonzoESC via Flickr // CC NC 2.0

The chain discretely prints Bible verses on the bottom of their cups and wrappers, though they’ve never discussed the inclusion publicly. The Snyders' son Rich, who ran the company after Harry’s death, began the practice in the late ‘80s, telling the company’s spokesman "It’s just something I want to do."

Around Christmas 1991, Snyder, a born-again Christian, aired a radio ad that said, "Ask Jesus to come and live in your heart today. Choose life by choosing Jesus. In-N-Out Burger wishes you a full and abundant life forever." The company took some flak for the ad.

13. LYNSI DOESN'T DISCUSS HER PERSONAL LIFE BECAUSE SHE'S WORRIED ABOUT OUTSIDE THREATS.

The In-N-Out president and heiress says she’s almost been kidnapped twice.

14. ALL OF THE IN-N-OUT HEIRS WORKED IN THE BACK.

Rich and Guy Snyder

A photo posted by In-N-Out Burger (@innout) on

Harry and Esther made their two sons, Guy and Rich, do entry-level work so that they wouldn't be spoiled. And even though she would own the company by the time she was 24, Guy's daughter Lynsi’s first job at In-N-Out was in the kitchen at a new store in Redding. "She started out like everyone else in prep work, coring tomatoes, peeling potatoes, and slicing onions," Orange Coast Magazine reported last year. "'Of course, I would cry every time,' she recalls with a laugh. Nevertheless, 'I was really excited to work there, because it was the family business. It was fun, and I thought it would make my dad happy.'"

15. IN-N-OUT HAS MADE A LOT OF MONEY.

Lynsi is potentially America’s youngest female billionaire (emphasis on potentially). But even if she’s not an actual billionaire yet, she might get there when she inherits full control of the company’s trusts when she turns 35.

16. HARRY WAS ON ATKINS BEFORE IT WAS A THING.

Neeta Lind via Flickr // CC BY 2.0

The "protein burger" on the Secret Menu is just the meat wrapped in lettuce, but it’s not a fad addition. Back in the ‘70s, Harry Snyder began ditching the bun because he was dieting. "Some people think that the protein burger came about recently because of all the Atkins dieters," general manager Carl Van Fleet said in 2004, "but it’s been around since the late 1970s."

17. IN-N-OUT ISN'T ABOUT TO START CHANGING ITS MENU.

cormac70, Flickr // CC BY NC-ND-2.0

Once in a generation, something new might officially be added to the menu. The only item Lynsi has added is sweet tea—and that's only in the newer Texas locations. The only other major menu addition of the past two decades? They started serving Dr. Pepper in 1996.

18. THE EAST COAST IS JUST NEVER GOING TO GET AN IN-N-OUT

In 2010, College Humor played a mean April Fools’ prank on New Yorkers by convincing passersby that In-N-Out was opening a location in the city. But because the company has such strict quality-control measures, they have a policy of not opening restaurants further than 500 miles from their in-house commissaries.