A young employee held a tray of McDonald's food on May 9, 1986.Trevor James Robert Dallen/Fairfax Media/Getty ImagesThe first McDonald's franchise opened in Des Plaines, Illinois, on April 15, 1955.Chicken nuggets were introduced to the menu in 1983.Motorhead and President Ronald Reagan were photographed eating at McDonald's in the 1980s.By the 1980s, McDonald's had already become a well-established fast-food chain with a well-known menu and dis…