What city in Colorado claims to invent the first sandwich that most people love eat?

The city of Boulder, Colorado, claims to be the birthplace of the first-ever cheeseburger sandwich. In 1930, Louis Ballast, owner of the Humpty Dumpty Drive-In, is said to have created a sandwich that combined a hamburger with a slice of American cheese. The cheeseburger quickly gained popularity and became a staple of American fast food.