Lemon trees grow in precarious, terraced plots on the steep cliffs that run between Positano and Vietri sul Mare along the Amalfi Coast. The almost year-round sunshine and salty sea air help produce a sweet-tart fruit with low acidity and an edible rind. This special varietal is called Sfusato Amalfitano, and the lemons are a registered and protected product. Visitors can tour the groves and participate in cooking classes or limoncello tastings with the Acetos, a family that has lived and farmed these lemons for six generations.