Generally, California brings to mind fancy avocado toast, green juice and more healthy eats—but it's also the birthplace of one of the great fast-food joints of our time. The regional chain known for killer burgers, fries and milkshakes wrangles major points in the West Coast vs. East Coast debate, and at this point, In-N-Out is basically a tourist attraction for visitors from around the world. Here's everything you need to know before you get to the drive-thru window.

1. In-N-Out has been in the burger game since the 40s.

The chain's founder, Harry Snyder, opened the first In-N-Out in 1948 in Baldwin Park, CA. The original spot, California's first drive-thru hamburger stand, was just barely 10 square feet. Harry bought fresh meat and produce for the restaurant daily, while his wife Esther handled the accounting out of their home around the corner.

2. The business is still family-run.

Harry Snyder's sons Rich and Guy took over the chain when their father passed away in 1976, keeping it running with help from their mother, Esther. Today, Harry and Esther's only grandchild is the owner.

3. It revolutionized drive-thru dining.

Instead of hiring carhops like other quick-service joints, Harry Snyder built his own two-way speaker box to allow guests to order and receive their meals without leaving the car. Most restaurants had just two lanes for drive-thru customers and a few tables outside—the first dining room restaurant didn't open until 1979!

4. The palm trees outside are symbolic.

In addition to signs with the iconic yellow arrow, customers can also spot In-N-Out from a distance thanks to the crossed palm trees planted out front of most locations. The founder was inspired by one of his favorite movies, "It's a Mad, Mad, Mad, Mad World," in which the characters race to find treasure buried under four crossed palm trees. Burgers and golden fries are just the kind of treasures we want to hunt for!

5. The burgers are super fresh.

At the beginning, all In-N-Out burgers were ground and formed into patties using a manual press—now the patties are made at company-owned facilities in California and Texas so the burgers don't need to be frozen. The two-patty Double-Double is a favorite that was added to the menu in 1963. They're tasty enough that one dude at them every day for a month.

6. Anyone can order off the secret menu.

In-N-Out embraces many of the burger variations that have become popular over the years, so it's totally okay to switch things up from the classic. You can order a Double Meat (two patties) or really load up on beef with the 3x3 or 4x4 (that's three and four patties, respectively), plus all the usual fixings. Vegetarians can opt for a Grilled Cheese (complete with lettuce, tomato, spread and onions) and those watching their carb intake might want the Protein Style, wrapped in lettuce instead of a bun. But there's one secret menu item that reigns supreme...

7. Customers invented the "Animal Style" burger.

Thanks to requests from diners, the chain introduced the über-popular, specialty burger back in 1961. It's a mustard-cooked beef patty topped with lettuce, tomato, pickles, extra spread and grilled onions. We even hacked the recipe so you can make Animal-Style Burgers at home.

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Flickr Creative Commons / vagueonthehow

8. You can even customize your fries.

Ordering the hand-cut French fries to go with your burger is a must, but there's not just one way to do it. In addition to the regular side, you can ask for fries light (less time in the fryer), well done (fried until extra-crispy), smothered in cheese, or Animal-Style, with cheese, special sauce and grilled onion bits.

9. In-N-Out fans are kind of a big deal.

The chain's devotees are a star-studded group. Beyoncé can't get enough of the burgers, Kim Kardashian chowed down on the cheese fries when she was pregnant, and Gigi Hadid once even turned the drive-thru into a runway when she placed an order on-foot in a full sequined gown.

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10. There are only a few places where you can get it.

The company got it's start in Cali, but eventually expanded over the years. Today there are locations in California, Nevada, Arizona, Utah, Texas and Oregon—but that's it. Fans on the East Coast will just have to wait patiently until the day they can bite into a Double-Double on their own turf!

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Flickr Creative Commons / Mike Mozart

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