The BIRKENSTOCK Madrid is the oldest member of the family of models, making it a veritable classic. Launched as a “gymnastics sandal" half a century ago, this simple single-strap model has gone on to become a firm fashion favorite. The contrasting outsole stands out strikingly against the upper and rounds off the look. The upper is made from the skin-friendly, hard-wearing synthetic material Birko-Flor® with a shiny patent coating.