Innocuous as it stands — just a 3-foot tall granite marker commemorating the invention of the cheeseburger in 1935 near the intersection of Speer Boulevard and Zuni Street — the structure carries controversy.

The monument now rests near a KeyBank, but it’s the former site of the Humpty Dumpty Barrel — considered to be Colorado’s first drive-in restaurant. It memorializes Louis Ballast, who lays claim to creating the American food staple.

“On this site in 1935 Louis E. Ballast created the cheeseburger. His restaurant, the Humpty Dumpty Barrel Drive In was Colorado’s first dive in and was commonly known as The Barrel. The cheeseburger trademark was registered by Mr. Ballast on March 5, 1935. Dedicated March 5, 1987,” the marker reads.

The only problem? Similar claims to cheeseburger glory in the form of a printed restaurant menu with a cheeseburger from 1934 in Louisville, Kentucky and the testimony of a line cook Pasadena, California in 1924, who alleges to have served it there, throws some cold water on Ballast’s hot stoves.

What is indisputable, though, is that Ballast began the trademarking process for the cheeseburger in 1935, although he never finished the process.

“That’s why I’m not a millionaire,” David Ballast, Louis’ son, told the Denver Post in 2011. Ballast also tried peanut butter and Hershey’s bars as toppings prior to settling on cheese, The Denver Gazette’s own John Moore previously reported.

“It was really a nice place. I was a kid when I was going there but there was a lot of older people, a lot of young kids gathering around there… Their cheeseburgers were delicious. My order was a cheeseburger and root beer,” said longtime Denver resident Rita Segura, who shared her memories while passing by the marker Monday, National Cheeseburger Day.