Since their introduction in 1941, M&M's have become an iconic American candy. M&M's is an abbreviation for the names of their creators, Forrest Mars and Bruce Murrie. For decades, consumers could only choose between chocolate and peanut M&M's, but since the 1990s, Mars, Incorporated has introduced a variety of specialty flavors. In 1998 M&M's became the "official candy of the Millennium," because MM means "2000" in Roman numerals. According to Mars, some 400 million M&M's are manufactured every day.

Mars, Incorporated began producing M&M's chocolate candies during World War II. They originally came in small, cylindrical tubes. The bag design, a deep chocolate brown, was introduced in 1948 and remains the same today. The candies were not stamped with the ubiquitous "M" until 1950, when a bag cost only 5 cents. At that time, the M was stamped in black.

Mars introduced the Peanut M&M in 1954, which was a significant year in the candy's history. The famous slogan "melts in your mouth, not in your hands" was introduced, and Mars unveiled the popular animated M&M's characters in television commercials.

In 1960, M&M's were available in yellow, green and red. Orange was added in 1976. Mars created a marketing campaign to add a new color in 1995. The general public was invited to vote on their favorite shade. Blue was the winner. Another "election" in 2002 added purple to the mix. In 1996, custom M&M's colors were introduced. Today, every shade of the rainbow is available to commemorate anything from weddings to births to graduations. Special messages can also be printed on the M&M's. Seasonal color mixes are available in red and green for Christmas and pastels for Easter.

Mars began marketing M&M's in a number of foreign countries in 1980, including Japan, Hong Kong, France and Germany. In 1982, the astronauts took them into space for the first time.

Until the debut of M&M's Minis in 1996, the candy only came in one size. The minis were packaged in small tubes, reminiscent of the original packaging. Three years later, Mars brought out Crispy M&M's, the first new flavor since Peanut M&M's were introduced 45 years earlier. Other flavors today include almond, dark chocolate and peanut butter. A line of M&M's Premiums, introduced in 2009, features gourmet flavors like raspberry almond, mint chocolate and mocha. Innovations come every few years now, with create-your-own, peanut butter and pretzel flavored among the latest offerings.

The M&M's animated characters have taken on a life of their own. Mars introduced Green in 1997 as the first female animated character. Orange, the paranoid crispy M&M, joined the gang in 1999. Red and Yellow continue to be the most popular characters, and appear in many commercials together, including a holiday classic where the pair encounters Santa. Today, an online game allows visitors to create their own M&M's characters using different eyes, hairstyles and accessories.

M&M's became a NASCAR sponsor in 1990, but the characters did not appear on a car until 1999. They quickly became a fan favorite, so M&M's became a primary NASCAR sponsor. Famous drivers of the M&M's car have included Ken Schrader, Elliot Sadler and Kyle Busch.