September 18 - National Cheeseburger Day
Sunday, 18 September, is "National Cheeseburger Day" is the US, but you can celebrate anywhere you are.
As far as "American food" goes, the cheeseburger might be the paradigm. Ground beef has been around forever, but the cheeseburger only came into being in the early 1900s. But what a popular sandwich invention it was!
What is the secret to its popularity? Umami. The "fifth taste." Umami is savory, and when you bite into a cheeseburger, that is what you get. It comes from grilled meat and cheese. Add in some sauteed mushrooms and bacon (both high in the glutamates which produce the umami taste), and you have an "Umami Bomb."
Whether you like your cheeseburger plain; or with lettuce, tomato, and onion; or smothered in chili; or hot off the barbecue ... treat yourself today (or anyday) to the epitome of deliciousness.
And don't forget the fries ;^)
Edit: This is from Wikipedia -
"Adding cheese to hamburgers became popular in the late-1920s to mid-1930s, and there are several competing claims as to who created the first cheeseburger. Lionel Sternberger is reputed to have introduced the cheeseburger in 1926 at the age of 16 when he was working as a fry cook at his father's Pasadena, California sandwich shop, "The Rite Spot," and "experimentally dropped a slab of American cheese on a sizzling hamburger."[