Back in 1955, McDonald's offered 15-cent hamburgers. At the time, its menu only offered nine items.
McDonald's packaging has gone through noticeable changes over the years. This is what it looked like in 1955, complete with its old mascot.
Ronald McDonald made his first appearance in 1963, and he has been around ever since.
McDonald's is continuing to make changes in order to turn its business around.
The company promoted Steve Easterbook to CEO in 2015, changed up the menu, started serving breakfast all day, and launched self-service kiosks, which allow customers to customize burgers with different premium toppings.
Burger King was founded in 1954. The Whopper was introduced to the menu in 1957. The sandwich has been on the menu — with its many variations — ever since.
Here's a Burger King Express in Valdez, Alaska in 1989.
Today, Burger King is launching multiple initiatives to compete in the latest fast-food wars and testing various different products, including the "Whopperito," its very own take on a burrito, which was launched in 2016.
This is the first-ever Wendy's. It opened in Columbus, Ohio in 1969.
This is the interior of the original Wendy's location. It closed its doors in 2007.
In 1970, Wendy's pioneered the first drive-thru window. It had a separate grill for quick service.
In 2012, Wendy's underwent a brand transformation. It redesigned its restaurants, innovated its menu, and improved its ad campaigns. In 2017, the chain announced that it would invest $30 million in improving the quality of its chicken.
This is the original design and logo of Taco Bell, which was founded in 1962.
55 years later, the chain has expanded to offer upscale dining at its four new "Cantina" restaurants, which also serve alcohol.
Here is a retro Kentucky Fried Chicken in Marietta, Georgia.
Colonel Sanders has been the face of KFC since it was founded in 1952.
Here's an old KFC "realistic play food" toy kit.
KFC has been rolling out a new design. The brand began testing the renovated restaurants in 2014, and seventy percent of the brand’s 4,500 restaurants will be updated by the end of 2017.
The original Dunkin' Donuts was founded in Quincy, Massachusetts in 1950 .
Today, there are more than 11,300 Dunkin’ Donuts restaurants worldwide. 8,500 of these are in the US.
The first Dairy Queen opened in 1940 in Joliet, Illinois.
77 years later, Dairy Queen still curls the top of its ice cream cones.
While most of Sonic's restaurants have kept the old-fashioned drive-in look, the restaurant chain's menu has changed quite a bit since the 1950s.
In 2016, Business Insider reported that there were 1.3 million drink combinations available at the chain, with lots of different flavors of slushes, shakes, Sonic Blasts, and other beverages on sale.
When White Castle opened in 1921 it sold a five-cent slider hamburger. Here's what the restaurant looked like in the 1930s.
This is a White Castle in 1981.
Today, the chain still sells its legendary slider.
Arby's was founded by Forrest and Leroy Raffel in 1964.
Arby's has undergone big changes in its menu and marketing over the past few years. Since 2014, it has remodeled 500 of its restaurants to resemble fast-casual chains and has plans for 200 more in 2017.
The first Hardee's opened in North Carolina in 1960.
In 1997, Hardee's was acquired by CKE Enterprises, the parent company of Carl's Jr. Hardee's restaurants eventually began serving Carl's Jr. food items and adopted its star logo.
This is the first Jack in the Box, which opened in San Diego in 1951.
This is a Jack in the Box restaurant in the 1960s.
The fast food chain has kept the same mascot for 66 years.
Dan and Frank Carney borrowed $600 from their mother to open the first Pizza Hut in Wichita, Kansas in 1958.
Today, Pizza Hut tries to compete not only with other pizza chains, but also with McDonald's and Kentucky Fried Chicken by having its own version of a value menu.
It's also trying to become more mobile friendly. Its new, "Visible Promise Time" feature allows customers to see when their order is being prepared and when it will arrive.