When A&W comes to mind, you instantly think of the Root Beer Float. The oldest restaurant franchise in America, the chain started as a root-beer stand in 1919 and its signature brew is still made onsite at restaurants, before being topped with creamy vanilla soft serve and presented in a frosty mug. A&W even invented National Root Beer Float Day.

This tiny burger is the foundation of a fast-food empire. White Castle's Original Slider, invented around 100 years ago, famously features a small, square patty with five holes that help it cook quickly. The burger is still sold the same way it always has been, too: steam grilled with onions and pickles and doled out by the sack.

The secret recipe for KFC Original Recipe Chicken was dreamed up at a petrol station in Corbin, Kentucky in the 1930s. Colonel Sanders decided to start making the fried chicken he grew up eating – cooked in a pressure cooker and seasoned with 11 herbs and spices – for customers. Today, it’s still one of the most craveable foods in the world and is sold in over 100 countries.

Discover these fascinating fast food facts

For 84 years, Krispy Kreme's Original Glazed doughnut – an inconceivably light, sweet treat whose recipe is a secret – has single-handedly carried the chain’s global success. Part of the wonder comes from the fact that you can watch the doughnuts being made through a glass screen in stores, in the factory section. Look out for a glowing red "Hot Now" sign, meaning you can enjoy them fresh off the line too.

Here are 25 other tasty facts you didn't know about Krispy Kreme

One of the most respected burger chains in the US, with legions of fans including celebrities, In-N-Out is famous for its Animal Style option on its Not So Secret Menu. Order this and you’ll get a classic burger, but with mustard cooked into the patty. It has been lauded by none other than late chef Anthony Bourdain.

Love this? Follow our Pinterest page for more food inspiration

These crispy-edged, soft-centred string fries are some of the best in the business. Introduced in 1949, they’re fried in veg oil and seasoned with beef flavouring (they used to be fried in beef tallow). They’re ordered as part of nearly every meal and sometimes on their own. There’s a reason the fast food chain is the largest buyer of potatoes in the world.

Follow the incredible story of how McDonald's conquered the world

Contrary to popular belief, the restaurant chain didn’t invent the hard shell taco. However, the small, crunchy beef, Cheddar and lettuce snack is arguably one of the most influential fast foods of all time. One of the first items on Taco Bell’s menu in the 1950s, it helped the chain grow to the size it is today, introduced Mexican-inspired food to millions of Americans and is still one of the brand's most popular dishes.

Though it’s seen as Big Mac’s biggest competitor, the Whopper actually predates its rival by 10 years. A 4oz (113g) beef patty topped with tomatoes, lettuce, mayo, ketchup, pickles and white onion in a sesame seed bun, it was positioned as a bigger, fancier version of what Wendy’s and McDonald’s had to offer at the time.

Selling an average of three million pizzas per day, Domino's is the largest pizza brand in the world. The majority of its sales are for its pepperoni pizza, a medium-thick, floppy crust delight featuring a coating of tomato sauce, bubbling cheese, crispy pepperoni slices and garlic dipping sauce. 

Now find out how you can make your fast food favourites at home

The first chicken sandwich sold by a fast food chain, Chick-fil-A's Original Chicken Sandwich is a toasted buttered bun filled with a breaded chicken breast and two pickles. It was added to Chick-fil-A's menu by founder Truett Cathy in 1964, after he tested hundreds of recipes, and it hasn’t changed since. Newer versions such as the Spicy Chicken Sandwich have joined the menu, but we reckon the original still takes some beating.

One of McDonald’s longest standing menu items is the controversial Filet-O-Fish. The divisive dish was added to the menu in the 1960s to encourage meat-abstaining Catholics to eat at the restaurant on Fridays and during Lent. The breadcrumbed white fish, American cheese and tartare sauce sandwich was a hit from the start and inspired other fast food outlets to bring out their own versions.

The iconic sandwich featuring thinly sliced beef, Arby’s Sauce (a tangy, spicy ketchup) or Horsey Sauce (a mayo and horseradish sauce) and a toasted sesame seed bun has been on the menu at Arby’s since the beginning in 1964. While the chain has added fancy new promotions such as a venison steak, crispy onion and juniper berry sandwich, the roast beef delight has true staying power.

Added to the McDonald’s menu in the 1960s, the Big Mac is one of the most famous burgers on the planet. It features two beef patties, a three-part sesame seed bun, Big Mac sauce, pickles, lettuce, chopped onion and cheese. It’s the chain’s signature item and so widely available around the world that The Big Mac Index is used as an economic tool.

Learn the incredible history of the Big Mac

A golden, crispy, turnover filled with sweet, cooked apple, McDonald’s Apple Pie joined the chain's menu in 1968 as its first dessert. Since its inception it has gained millions of fans, despite a number of recipe updates including switching from fried to baked and reducing its sugar content.

The most famous breakfast item at McDonald’s, the Egg McMuffin was added to the menu in the 1970s. It features a fried egg, American cheese and bacon on a toasted English muffin and for most of its history it has only been available in the early morning. Nonetheless the breakfast menu reportedly manages to generate around a quarter of the company’s annual revenue.

Munchkins were introduced at Dunkin’ Donuts in the 1970s. Invented as a way to use excess dough cut from the doughnut holes, the bite-sized treats are now so popular they’re made with a separate machine.

Subway’s flagship sandwich, Italian BMT was introduced 10 years after the chain opened, in 1975. The ultimate savoury, on-the-go lunchtime treat, it features pepperoni, salami and ham, and your choice of salad and bread. 

Now check out the fast food chains we wish never closed

A fast food staple, golden, crispy Chicken McNuggets were added to McDonald’s menu in the 1980s and remain an enduring favourite. They’re so popular, in fact, that they survived a rumour that they're made out of pink slime and people buy them in bumper boxes.

The Blizzard was introduced in 1985 and was so popular it sold some 175 million units in one year. Still to this day, at Dairy Queen stores, employees flip the chunky, frozen, soft-serve treat upside down to prove just how thick it is. Also, every month you can find a different featured Blizzard of the month.

When Five Guys opened in the 1980s, it offered a new fast-food experience: freshly cooked, juicy beef burgers with unlimited free toppings such as pickles and grilled mushroom, plus bacon and cheese, in a squishy bun. Considered to be more upmarket than its competitors, it completely took off, franchising nationwide then globally from the 2000s. The Bacon Cheeseburger remains a fan favourite.

Panda Express' signature Orange Chicken was created by a French-trained Taiwanese chef at one of its restaurants in Hawaii in 1987. Now you'll find the sweet and spicy fried chicken dish at numerous other outlets, plus recipes allowing fans to make it at home.

Now try to guess these fast food items from their close-ups

Many credit 1990s chain Chipotle for starting the lunch bowl trend with its customisable burrito bowls featuring rice, beans, protein (such as chicken, barbacoa or carnitas), salsa, salad and cheese. It's a best seller at the Mexican fast-casual spot, likely because it offers value for money and makes the perfect work desk lunch.

Next find out the most historic fast food joint in your state

It’s not one of the chain’s original items, but since the McFlurry was introduced in Canada in 1995, it has been an integral part of McDonald’s menus all around the world. The ice-cream dessert features soft-serve and candy in a cardboard cup with a lid and a chunky hollow spoon. Over the years, McFlurries have come in a tonne of tasty flavours including Oreo, M&M’s and KitKat.

Want more? See if you remember these fast food logos from past times

When Shake Shack opened in the early 2000s, its aim was to serve simple, great-quality classic American burgers. The Shackburger (the go-to order) features a juicy, smashed patty, melted American cheese, lettuce, tomato and ShackSauce (a slightly spicy combo of ketchup, mayo, mustard and pickle brine) in a buttered, griddled potato bun. Judging by the queues outside its first location in New York and its rapid international expansion, it’s one that'll remain a favourite for decades to come. 

This whopping burger features two beef patties, six pieces of bacon, American cheese, ketchup and mayo. Dreamt up in 2007 to boost sales at Wendy’s, it quickly became one of fast food’s most successful introductions. In less than a year it sold more than 68 million units and it has spawned countless new promotions such as Baconator fries, Breakfast Baconator and Son of Baconator.

Now discover how Wendy's conquered North America