Observed on September 18 in the USA, this food holiday celebrates the nation’s enormously popular burger with a slice of cheese.

Legend has it that the sandwich was invented by teenage fry cook Lionel Sternberger in 1926 at his father's shop, The Rite Spot, in Pasadena, California.

Today, Americans consume approximately 50 billion burgers each year, and cheeseburgers are particularly popular — 74% of burgers are served with added cheese.

Look for special deals on cheeseburgers at fast food restaurants on this day.