The Grilled Cheese sandwich is a type of food where cheese is placed between two slices of bread that is fried, toasted, or broiled.
The practice of creating a hot cheese sandwich (where the bread is toasted and the inside cheese is heated to a point of melting) began in the 1920s as sliced breads and processed cheeses became more widely available. The original versions, however, contained one slice of bread, topped with cheese. The practice of adding a top, toasted slice of bread became popular in the 1960s. A cold version, without toasting and melted cheese, is simply called a cheese sandwich.
Today, the grilled cheese sandwich is a very popular food in the US with a grilled cheese convention held annually in Los Angeles in its honor.