National Hamburger Day: Where To Burg In ChicagoHappy National Hamburger Day! The modern burger, as we know it, was basically invented by White Castle. Yes, it was their sliders that caused this delight to be craved by all of America (though this was in the 1920s, before Crave Cases existed). With that said, you can do better than White Castle. It is National Hamburger Day after all.