M&M's Just Turned 75. Here’s How It Kept Consumers Interested for So Long

And became America's best-selling candy

As you read this, M&M's—the best-selling candy in America, the treat that Mars makes 400 million of every day, and the milk chocolate that melts in your mouth and not in your hand—is marking its 75th birthday. More on that in a moment. First, a quiz: Name the two forces that were instrumental to the invention of M&M's.