A Pretzel (German: Breze(l)) is a type of baked bread product made from dough most commonly shaped into a twisted knot. Pretzels originated in Europe, possibly among monks in the Early Middle Ages. The traditional pretzel shape is a distinctive nonsymmetrical form, with the ends of a long strip of dough intertwined and then twisted back into itself in a certain way. In the 2010s, pretzels come in a range of different shapes. Salt is the most common seasoning for pretzels, complementing the washing soda or lye treatment that gives pretzels their traditional skin and flavor through the Maillard reaction; other seasonings include various cheeses, sugars, chocolate, glazes, seeds, or nuts. There are several varieties of pretzels, including soft pretzels, which must be eaten shortly after preparation, and hard-baked pretzels, which have a long shelf life. Worldwide pretzels worth a billion dollars are sold annually.