Tipped as the third largest burger chain on the planet (trumped only by McDonald's and Burger King), Wendy's has been doling out delicious square-shaped hamburgers since 1969. But how did Wendy's go from a single Ohio restaurant to a fast-food titan with thousands of locations? Here, we dive back in time and reveal how this burger giant conquered North America.

Wendy's began with Dave Thomas, a man from humble beginnings who had a vision of what the perfect hamburger and fast-food joint should look like. In his early career, Thomas spent time working as a chef at Fort Wayne's Hobby House restaurant, and later in franchises of KFC owned by the same family. These experiences whetted Dave's appetite for a long-term career in the fast-food world, and he soon decided to set out on his own.

Dave decided to call his fast-food spot after his daughter Melinda, nicknamed "Wendy". In an entry on the chain's blog, Wendy Thomas remembers the moment her father told her he planned on opening a restaurant, and that it would be named "Wendy’s Old Fashioned Hamburgers". Things moved quickly after that. Soon Wendy was dressed in the iconic blue and white dress, with her hair cinched into pigtails, and was being photographed at the opening of her dad's new hamburger joint. She's been the face of the chain ever since.

Dave's vision for a quick-serve, family-friendly hamburger joint (partly inspired by his love of the Kewpee Hamburgers chain) was soon a reality. The original Wendy's opened on 15 November 1969 and was located at 257 East Broad Street in Ohio's capital city, Columbus. And the laid-back restaurant was soon a favourite for plenty of burger-loving locals.

Wendy's signature was (and is) its square-shaped beef patties, which spill temptingly from the confines of a pillowy white bun. The chain also won dessert-loving hearts with the Frosty®: a frozen chocolate ice-cream treat that served as the perfect finish to any Wendy's meal.

By the 1970s, Wendy’s was making fast-food history. In November 1970, the joint pioneered what Wendy's now terms as the world's "first modern drive through". Back then, Dave called it a “Pick-Up Window” and took delight in schooling customers on how to use the new-fangled speaker system.

Learn more about the history of the drive-thru here

By the mid-1970s, business was booming and Dave decided to take his burgers further north. In September 1975, the very first restaurant outside of the USA opened up in Hamilton, Ontario, Canada. America's northern neighbour loved the straight-sided hamburgers and there are still some 386 Wendy's locations in Canada today. Pictured here is a modern joint in Hamilton, ON.

Dave Thomas was not one to rest on his laurels and by the late 1970s, he decided it was time to make serious use of Wendy's marketing budget. Wendy's "hot and juicy" hamburgers made their TV debut in a commercial shown from April 1977 – and the chain's stint on the silver screen seemed to work wonders.

Just a year after the airing of the first TV commercial – and less than a decade after the first restaurant launched – Wendy's opened its 1,000th hamburger joint in March 1978. The location to bear this honour was the Wendy's in Springfield, northern Tennessee. This nostalgic black and white ad hails the opening of yet another joint in Bryan, Ohio, a year later in 1979.

From one landmark year to another, it was in 1979 that Wendy's introduced its once uber-popular salad bar. A light alternative, or accompaniment, to Wendy's belly-busting burgers, it was a quick hit that remained well-loved right into the Eighties. The salad bar would survive up until the Noughties when boxed salads came to the fore. This snap is from a Wendy's spot in the Philippines, which has kept the concept alive.

Fast-forward to the Eighties and another new Wendy's staple was born. The humble baked potato graced menus from October 1983 and it has had serious staying power. Die-hard Wendy's fans still swear by the sour cream and chive baked potato, or a fluffy spud heaving under steaming chilli and oozing cheese.

Wendy's wedged itself even further into America's psyche with the landmark "Where's the beef" commercial that aired in January 1984. The hit ad featured a cheeky octogenarian named Clara Peller, who peered at a lacklustre hamburger and exclaimed "Where's the beef?" – a voiceover then promised that generous Wendy's hamburgers offered customers "more beef and less bun". The slogan is still famous to this day and Wendy's says that its revenue grew by a third as a result. See more vintage food ads from your childhood here.

But by the late 1980s, Wendy's unveiled a brand new TV star: founder Dave Thomas himself. The fast-food mogul appeared in his first TV commercial in April 1989 and was much loved by the public. After this initial debut, he promoted his beloved Wendy's in upwards of 800 TV adverts.

You're probably well familiar with McDonald's modern Saver Menu – but did you know that Wendy's launched its Super Value Menu right back in 1989? Wendy's tips itself as "the first to introduce the concept of a Super Value Menu", which comprised nine rotating items for less than a dollar each day, from classic burgers to crispy chicken nuggets.

Though the chain has made the most ground in North America, in the late 1980s, Wendy’s opened various global outlets (from Mexico to Greece to the Philippines) with varying degrees of success. Wendy’s was also open in the UK throughout the Nineties, but had closed by the early 2000s. Rumour has it, it might be making a comeback though... A modern Wendy's outlet in the Philippines is pictured here.

Wendy’s went on something of a health kick in the early Nineties. This was the era that the chain introduced its grilled chicken sandwich (in 1990) and also its boxed salads (in 1992). Diners watching their waistline could feast on the lighter chicken burger, or choose between a Taco Caesar, Deluxe Garden or Grilled Chicken salad. 

In 1996, Wendy's unveiled another enduring menu favourite: the Spicy Chicken Sandwich. In fact, Wendy's claims to be the very first fast-food chain to introduce a zingy chicken burger. Still available today, it's a fiery golden-fried chicken breast cased in a bun with lettuce, tomato and mayonnaise. 

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The fast-food world went into mourning in January 2002, when beloved Wendy's founder Dave Thomas died of liver cancer aged 69. This touching sign at a Wendy's in Cincinnati, Ohio paid tribute to the late fast-food pioneer.

Wendy's continued to innovate even after the death of its pioneering founder. In August 2006, the chain's menu gained a delectable addition in the form of the new Vanilla Frosty®. The moreish chocolate version had been sating sweet-toothed punters for decades and the vanilla alternative was a winner too.

Another legend of the Wendy’s menu was born in 2007 in the form of the Baconator®. Still a crowd favourite, this mammoth burger consists of a double beef patty, plus Applewood smoked bacon and cheese. The burger legend span off another iteration in 2012, too: the Son of Baconator® is a smaller, but equally delicious version with a little less bacon and smaller patties.

It’s always risky business when a chain switches up a long-standing menu option – but it was a risk that paid off in this case. In November 2010, the Wendy's fries of yore were replaced with a "natural-cut" option made from skin-on russet potatoes and finished with sea salt. And the chain hasn't looked back since. 

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Wendy’s didn’t stop at its fries, either. In October 2011, the chain introduced a new and improved burger line called Dave’s Hot ‘N Juicy Cheeseburgers. The range's USP was its "fresh never frozen" beef, which came in a thicker patty than before, plus high-quality toppings and a buttery bun. "Est. 1969 – perfected 2011" was the tagline.

It wasn’t just the Wendy’s menu that was overhauled in the early 2010s, either. In 2012, Wendy’s began a dramatic shape-shifting process that saw sleek new restaurants and, most dramatic of all, a transformed logo in 2013 – the first big logo change in three decades. The blocky letters were gone, as was the “Old Fashioned Hamburgers” line, and, for the first time, Wendy’s pigtails spilled from the circular frame that surrounds her face. Now it’s hard to imagine the iconic logo looking any other way.

The year 2013 also saw the opening of a brand new flagship Wendy's restaurant in Dublin, Ohio – around 13 miles (21km) from the original Columbus location, which closed in 2007. As well as a working Wendy's, this landmark joint is a love letter to Dave Thomas and the chain itself, featuring information plaques and nostalgic restaurant memorabilia. 

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In addition to giving its restaurants a swish new look throughout the 2010s, Wendy's rolled out some suitably mod cons too. First came the Wendy's app, which was launched in 2012, and then the introduction of self-order kiosks from 2017 (a trend mirrored by other fast-food heavyweights). By 2019, this self-service tech was in around two-thirds of Wendy's restaurants. 

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Wendy's got 2020 off to a tasty start when it launched its first breakfast menu. Introduced in March, the tempting morning range includes a Honey Butter Chicken Biscuit – a golden chicken fillet with a buttermilk biscuit and maple honey butter – and, best of all, the Breakfast Baconator®, with added sausage and egg.