Mastic—the fragrant resin cultivated exclusively on southern Chios—gives local cuisine a distinctive flavor. Used in everything from cakes to liqueur, mastic has been the mainstay of the local economy since the Middle Ages. The masticohoria (mastic-producing villages) were fortified with walls and watchtowers to protect supplies of this precious resin from pirates and smugglers. Unchanged since Byzantine times, the village of Mesta is dominated by a medieval tower from which you can look out across the town. Walk along the walls and rooftops or get lost in the maze of cobbled lanes, deliberately designed to confuse outsiders. In Pyrgi, all the houses are completely covered with black-and-white geometric patterns, an equally disorienting spectacle.