It's National Pretzel Day today (Friday). It's a day to enjoy and celebrate what many believe to be the world's oldest snack, with roots going as far back as the sixth century. Today, there are so many kinds of pretzels to enjoy. Salted and unsalted, straight or twisted, thick or thin, hard or soft, and so on. There are even flavored pretzels and pretzel crackers. There's really no shortage of ways to enjoy a pretzel.