Burger King’s Whopper is on its way to being an old timer, having logged 55 years in fast-food history. During this time, we’ve seen Burger King go through vast changes as a brand (with, it must be said, a few questionable marketing decisions and unforeseen PR fails along the wa)y. However, the chain hasn’t made any dramatic changes to its signature burger over the years.

That said, the Whopper has not been completely trapped in time. According to a timeline drawn recently by Nation’s Restaurant News, tweaks to the formula have tended to be simple over the years, relying on tried-and-true flavor combinations—adding bacon, for example, or swapping in a new condiment.

The Bacon Whopper, one of the first remixed Whoppers to hit the market, came on to the menus in 1991. Since then, there has also been the 1996 Fiesta Whopper (Cheddar or American cheese, and bacon) and the 2011 California Whopper (Swiss cheese, guacamole, and thick-cut hardwood smoked bacon), among others.

[via Nation’s Restaurant News]