In 610, a monk twisted some leftover dough into the shape of crossed arms and gave it to children as a reward for learning their prayers. Pretzels were a hit across Europe, and nine centuries later, when the Turks were tunneling under the walls of Vienna, it was the early-bird pretzel bakers who heard them and sounded the alarm. Even today, the coat of arms of the Viennese bakers proudly bears a pretzel. But it was the Pennsylvania Dutch who perfected what would become a famous Philly snack. According to The New York Times, the soft pretzel, sprinkled with salt and smothered in mustard may be the definitive street food.