<p class="ingestion featured-caption">Product shot of a McDonald's Big Mac hamburger in 1977.Henry Groskinsky/The LIFE Images Collection/Getty Images</p><ul class="summary-list"><li><strong><strong>The <a href="https://www.businessinsider.com/weirdest-coolest-glamorous-mcdonalds-restaurants-in-the-world-2020-5" rel>first McDonald's franchise</a> opened in</strong></strong> Des Plaines, Illinois, on April 15, 1955.</li><li>By the 1970s, McDonald's had grown into an increasingly popular fast-food establishment.</li></ul><p>National Burger Day is May 28, and no fast-food chain knows burgers quite like <a href="https://www.businessinsider.com/surprising-facts-mcdonalds-hamburgers">McDonald's</a>. </p><p>In the 1970s, less than a decade into its operation under businessman Ray Kroc, McDonald's was already a thriving company that had served millions of customers.</p><p>Richard and Maurice "Mac" McDonald opened the <a href="https://www.businessinsider.com/mcdonalds-history-started-barbecue-restaurant-1940s">first McDonald's in 1940</a> as a barbecue restaurant, and Kroc opened its first franchise location in Des Plaines, Illinois, on April 15, 1955. That year, <a href="https://www.mcdonalds.com/us/en-us/about-us/our-history.html" target="_blank" rel="nofollow noopener">he also founded McDonald's System, Inc.</a>, which would become the McDonald's Corporation we know today.</p><p><a href="https://www.businessinsider.com/what-mcdonalds-was-like-1950s-2020-7" rel>By 1958</a>, McDonald's had sold 100 million burgers, and the restaurants had adopted a signature design style prominently featuring the chain's iconic "golden arches." In 1961, Kroc bought the McDonald brothers out, and by the 1970s, the company was going from strength to strength.</p><p>Today, there are around 34,000 McDonald's locations around the world, but there are also new challenges. Consumers are being more <a href="https://www.businessinsider.com/amazon-starbucks-earnings-how-cautious-us-consumers-spending-sales-decline-2024-5">cautious about their spending</a>, so the brand's focus this year is on offering <a href="https://www.businessinsider.com/mcdonalds-value-diners-cut-back-fast-food-restaurant-price-increases-2024-5">affordable meal options</a> amid surging global food prices, its execs said in May.</p><p>Here's what it was like to eat at McDonald's in the 1970s.</p>