the Big Mac was actually invented by Jim Delligatti, a McDonald's franchisee running restaurants in Uniontown, Pennsylvania, back in 1967. he came up with it at the franchise level to compete with bigger burgers from local competitors, it did so well locally that McDonald's corporate rolled it out nationally in 1968. Delligatti kept running his McDonald's franchises for decades afterward, ended up owning dozens of locations and doing very well financially, and passed away in 2016 at age 98.
98 years old is a good run, and living to see your invention become a global icon is a pretty rare thing
wild that one franchise owner's local idea became one of the most recognizable food items on the planet