For decades, people all over the world have enjoyed munching on these button-shaped, chocolate-filled treats with an “m” distinctively printed on each of their candy shells. But what most people don’t realize is just how wildly popular M&M’s really are. The M’s actually represent the surnames of the candy’s founders, Forrest Mars, Sr. and Bruce Murrie, both Americans.

Not only is M&M’s among the world’s best-selling candies, it also has one of the world’s most recognizable and well-liked slogans:

Melt in your mouth, not in your hand. The original candy had a milk chocolate filling, but other popular variations now exist,

such as peanut butter, almond, pretzel, crispy, dark chocolate, coffee nut, strawberry nut, caramel and white chocolate.

The M&M range has extended from chocolate candies to groceries, merchandise and toy novelties.